WO1983001155A1 - Semiconductor laser with conductive current mask - Google Patents
Semiconductor laser with conductive current mask Download PDFInfo
- Publication number
- WO1983001155A1 WO1983001155A1 PCT/US1982/001171 US8201171W WO8301155A1 WO 1983001155 A1 WO1983001155 A1 WO 1983001155A1 US 8201171 W US8201171 W US 8201171W WO 8301155 A1 WO8301155 A1 WO 8301155A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- semiconductor laser
- fabricated
- layer
- active region
- current mask
- Prior art date
Links
- 239000004065 semiconductor Substances 0.000 title claims abstract description 32
- 238000005253 cladding Methods 0.000 claims description 21
- 239000000758 substrate Substances 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 10
- 238000005086 pumping Methods 0.000 claims description 5
- 230000000903 blocking effect Effects 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims 2
- 230000001105 regulatory effect Effects 0.000 abstract 1
- GPXJNWSHGFTCBW-UHFFFAOYSA-N Indium phosphide Chemical compound [In]#P GPXJNWSHGFTCBW-UHFFFAOYSA-N 0.000 description 12
- 230000012010 growth Effects 0.000 description 8
- 229910052581 Si3N4 Inorganic materials 0.000 description 7
- 238000005530 etching Methods 0.000 description 7
- 229920002120 photoresistant polymer Polymers 0.000 description 7
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 7
- 230000000737 periodic effect Effects 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- SAOPTAQUONRHEV-UHFFFAOYSA-N gold zinc Chemical compound [Zn].[Au] SAOPTAQUONRHEV-UHFFFAOYSA-N 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 3
- 229910052721 tungsten Inorganic materials 0.000 description 3
- 239000010937 tungsten Substances 0.000 description 3
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- MODGUXHMLLXODK-UHFFFAOYSA-N [Br].CO Chemical compound [Br].CO MODGUXHMLLXODK-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- XPDWGBQVDMORPB-UHFFFAOYSA-N Fluoroform Chemical compound FC(F)F XPDWGBQVDMORPB-UHFFFAOYSA-N 0.000 description 1
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- 229910000927 Ge alloy Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- BYDQGSVXQDOSJJ-UHFFFAOYSA-N [Ge].[Au] Chemical compound [Ge].[Au] BYDQGSVXQDOSJJ-UHFFFAOYSA-N 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- RZVXOCDCIIFGGH-UHFFFAOYSA-N chromium gold Chemical compound [Cr].[Au] RZVXOCDCIIFGGH-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/12—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
- H01S5/1228—DFB lasers with a complex coupled grating, e.g. gain or loss coupling
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
- H01S5/042—Electrical excitation ; Circuits therefor
- H01S5/0425—Electrodes, e.g. characterised by the structure
- H01S5/04254—Electrodes, e.g. characterised by the structure characterised by the shape
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
- H01S5/06203—Transistor-type lasers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
- H01S5/06209—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in single-section lasers
- H01S5/0622—Controlling the frequency of the radiation
Definitions
- This invention relates to semiconductor lasers and, more particularly, to semiconductor lasers having a current mask.
- One type of laser which does not require end mirrors is the distributed feedback lasers described in U. S. Patent 3,760,292 issued September 18, 1973 to H. W. Kogelnik et al.
- the gain medium or the index of refraction is modulated at periodic intervals in order to provide reflections along the entire length of tne gain medium.
- One form of distributed feedback laser that is proposed in the Kogelnik et al patent is a semiconductor laser in which a current mask is positioned within the laser structure in order to permit pumping or energizing current to pass through the active region of the laser only at periodic intervals along the length of the laser. Such a laser is shown in FIG. 5 of the Kogelnik et al patent.
- the device is a permeable base transistor wnose base consists of a layer of tungsten that has been patterned into a 3200 ⁇ period grating layer which layer is epitaxially embedded in a single crystal of n-type gallium arsenide.
- This transistor wherein the base is a grid-like metallic structure is said to provide many advantages over gallium arsenide field effect transistors.
- This transistor is not a laser, and the present invention relates to the recognition of the utility, and the means for incorporating, the new technology in laser devices.
- a grid-like conductive current mask is fabricated between the active region in a semiconductor laser and one of the electrodes between which the pump current flows.
- Changing the potential that is provided to this conductive current mask can regulate the light output from the semiconductor laser and also provide a means for adjusting the output wavelength in those lasers where the conductive current mask is sufficiently close to the active region to cause it to function as a distributed feedback laser.
- the conductive current mask is placed in a lightly doped buffer layer so that maximum modulation of the depletion depth around the current is obtained. Doping of this buffer layer must be sufficiently great, however, so that sufficient current to operate the laser is available.
- a semiconductor laser structure is etched in order to establish a pattern of grooves or notches over the active region along the length of the laser structure.
- a conductive terminal is deposited over the top parts of the notches that are not affected by the etching, and a conductive terminal is deposited over the entire bottom of the semiconductor laser structure thereby forming the two terminals through which the pump current flows.
- a third conductive layer is deposited at the bottoms of the grooves or notches to form the gate electrode which controls the pump current.
- a cladding region is epitaxially grown over the active region, and growth is terminated so that a conductive metallic grid can ioe deposited over the cladding layer.
- FIG. 1 is a pictorial drawing of a section of a semiconductor laser constructed in accordance with the present invention.
- FIG. 2 is a cross sectional diagram of the device illustrated in FIG. 1;
- FIGS. 3 and 4 are top and end views, respectively, of a second embodiment constructed in accordance with the present invention.
- FIG. 5 is a cross sectional diagram of the device illustrated in FIGS. 3 and 4. Detailed Description
- FIG. 1 A cross sectional view designated by the numeral 2 in FIG. 1 is shown in FIG. 2. The features and layers of this device are exaggerated in order to illustrate the construction.
- the device as shown is constructed, for example, by growing an epitaxial n-type buffer layer 11 of indium phosphide on an n+ substrate 10 of indium phosphide. This is then followed by an epitaxial growth of a quaternary layer 12 having a composition which will lase at the chosen wavelength. For tne materials system used in this device using indium, gallium, arsenic and phosphorous, a wavelength of 1.3 ⁇ m would be typical. The active quaternary layer 12 is then covered by a cladding layer 13 of p-ty ⁇ e indium phosphide which is grown relatively thick (about 2.5 ⁇ m) for the chosen wavelength of 1.3 ⁇ m .
- the cladding layer is then followed by the growth of a contact layer 14 of high conductivity p-type indium phosphide or quaternary material.
- the doping of cladding layer 13 should be sufficiently light so that the grid structure to be described hereinafter will be able to pinch off a channel width of about ⁇ /2 where ⁇ is the period of the grid structure. However, the doping must be sufficiently high to carry the necessary currrent to operate the laser.
- the entire top structure of the epitaxially grown device is then covered with a silicon nitride layer 15.
- Silicon nitride layer 15 is then coated with a photoresist, and the photoresist is exposed to produce a pattern which will permit etching of the layers in the indented areas of the device illustrated by the pictorial view in FIG. 1.
- This etching is initiated by a reactive ion etch using CHF 3 or a CF 4 +O 2 mixture in a plasma etch geometry to cut through the silicon nitride layer.
- This step is then followed by a reactive ion etch using pure Cl 2 in order to cut away all of contact layer 14 and approximately 1 ⁇ m of tne indium phosphide cladding layer 13 in the areas being etched.
- the device will begin to resemble the one illustrated in FIG. 1.
- a 5 second immersion of the device in concentrated hydrochloric acid is used to smooth the InP and slightly undercut the silicon nitride layer in order to produce an overhang of the silicon nitride layer of approximately 0.2 ⁇ m as illustrated in FIG. 1.
- This overhang is desirable in order to prevent the material which is deposited in the following step from adhering to the sidewails of the posts in the corrugated pattern produced during the reactive ion etch.
- the etching may be wholly accomplished with HCl alone. It is important that the mask be oriented as shown in FIG. 1 so that the side walls of the corrugated pattern be (01 ) or (011) crystal planes after HC1 etching.
- a material that, will form a good blocking contact with the cladding material is then deposited over the top surface of the device in order to create a gating electrode 16 which exists not only in the bottom-most regions of the notches that are created but also extends out over portion 26 of the cladding region which is exposed at the front edge of the device illustrated in FIG. 1.
- a Dlocking contact is defined as one which will cause a depletion of the surrounding material when the appropriate bias is applied. This action can be provided by reverse biased p-n, Schottky barrier, or metal- insulator-semiconductor junctions. In the embodiment illustrated in FIG.
- the gating electrode can be fabricated from a gold-germanium-alloy. Firing at a suitably elevated temperature may be used to improve the blocking quality of the gate.
- the gold-germanium that is deposited over the mask covering tne ridges is then removed by using the appropriate resist stripper to remove the photoresist mask, or by using sodium hydroxide to remove a titanium+ aluminum mask.
- a second resist pattern is then formed over the device to create windows in the top posts of the corrugated pattern.
- a plasma etch can be used to cut through the silicon nitride in these windows and a gold-zinc layer 17 can then be deposited in the windows and fired if necessary in order to produce a good ohmic contact with the high conductivity contact layer 14.
- a third mask pattern using a photoresist material is tnen utilized to create a chromium gold layer 18 which not only makes contact with the windowed layers 17 but also extends out over the rear portion of the device shown in FIG. 1 in order to provide an extended contact to the anode of the diode which has been constructed.
- the devices on a single wafer can then be separated either by sawing or by using a bromine-methanol solution. It should be apparent to those skilled in the art that end mirrors can then be formed by cleaving or by a suitable etching procedure in those cases where the device may be part of a more complicated integrated optics structure.
- the device shown in FIGS. 1 and 2 is utilized by applying a positive potential to anode contact 18 and a negative potential to the cathode contact 19 which is a gold-zinc contact that has been deposited over the entire bottom surface of substrate 10. Application of a negative potential to the gating electrode 16 then creates depletion regions of the type shown and designated in FIG. 2 as regions 21.
- gating electrode is not only a current mask but is a current mask that can change its degree of effectiveness depending on the potential that is applied.
- a second embodiment of the present invention can he constructed to provide a device of the type illustrated in FIGS. 3, 4 and 5.
- FIGS. 3 and 4 are top and side views of the device
- FIG. 5 is a cross sectional view of the device through a plane designated by the numeral 5 in FIG. 3.
- This embodiment is constructed by first growing a ⁇ -ty ⁇ e buffer layer 41 of indium phosphide on p+ substrate 40 of indium phosphide. This growth is followed by an undoped active quaternary layer 42 and an n-type cladding layer 43 of indium phosphide.
- cladding layer 43 is grown to a thickness (d) that is sufficiently small to permit the evanescent field of the optical mode to reach its top surface.
- the growth of layers 41, 42 and 43 illustratively involves the preparation of a (100) cadmium or zinc doped substrate with a Bromine-methanol polish-etch.
- the substrate is inserted into the liquid phase epitaxial system and heated to approximately 650 degrees C and permitted to cool .at a rate of about 0.5 degrees C per minute, while melts suitable for growing the first set of layers shown in FIG. 5 are alternately slid into position on the substrate.
- the device is removed from the liquid phase epitaxial system and the cladding layer 43 is immediately coated with a photoresist and exposed with the desired grating period, ⁇ . If distributed feedback operation is desired, the period, ⁇ , is chosen to provide Bragg reflection at the laser wavelength.
- a tungsten or conductive carbon gating electrode 48 may be evaporated over the photoresist pattern. If desired, shallow grooves may first be formed by plasma etching in order .to allow the tungsten or carbon gating electrode 48 to be recessed into the surface of the n-type cladding layer 43. This recessing can provide a planar surface for the growths which are to follow. After solvent cleaning, the entire substrate is then placed into the liquid phase epitaxial system and a lightly doped n-type top buffer layer 44 of indium phosphide is grown over the gating electrode 48. This top buffer layer 44 is followed by an n-type cap layer 45 of indium phosphide and a heavily doped quaternary contact layer 46.
- gating electrode 48 Contact is made to the gating electrode 48 by etching channels along the entire length of the device as illustrated in FIGS. 3 and 4.
- a cathode electrode 47 of gold and tin is then deposited over the entire length of the device, and a gold-zinc anode electrode 49 is formed over the entire bottom surface of substrate 40.
- the gating electrode under these circumstances can be utilized to modulate the level of the laser output, riigh modulation efficiency and speed will be provided through the transistor action of the gating electrode. if, however, tne gating electrode is brought to within a wavelength of the active quaternary layer and the period ⁇ chosen to meet the Bragg criteria, distributed feedback action will be added by the resulting spatially periodic gain. In the latter case all of the reflections required can be provided by the gating electrode, and the en ⁇ mirrors are no longer necessary, thereby permitting the ⁇ evice to be incorporated into a complex integrated optics structure. Wavelength control is expected to be possible while the laser provides a constant output by simultaneously varying the anode bias and the voltage applied to the gating electrode. Again, high modulation efficiency and speed is realized by modulating only the gate electrode.
- Wnat has been described hereinabove are two illustrative embodiments of the present invention.
- the first describes a p on n configuration while the second describes an n on p configuration.
- Two more embodiments are possible by interchanging n for p and vice-versa in both cases, provided only that the associated contacting materials are also changed in accordance with the layer to which they are applied.
Abstract
Semiconductor laser wherein a grid-like conductive current mask (16) is fabricated between the active region (12) of the laser and one (18) of its electrodes. In one embodiment, the conductive current mask is fabricated in the bottom regions of a corrugated pattern that is created along the length of the semiconductor laser. In a second embodiment, the conductive current mask (48) is totally embedded within a lightly doped layer (44) that is grown proximate to the active region. The grid structure provides a novel means for regulating the light output of the laser.
Description
SEMICONDUCTOR LASER WITH CONDUCTIVE CURRENT MASK
Technical Field This invention relates to semiconductor lasers and, more particularly, to semiconductor lasers having a current mask. Background of the Invention
One type of laser which does not require end mirrors is the distributed feedback lasers described in U. S. Patent 3,760,292 issued September 18, 1973 to H. W. Kogelnik et al. In the distributed feedback laser the gain medium or the index of refraction is modulated at periodic intervals in order to provide reflections along the entire length of tne gain medium. One form of distributed feedback laser that is proposed in the Kogelnik et al patent is a semiconductor laser in which a current mask is positioned within the laser structure in order to permit pumping or energizing current to pass through the active region of the laser only at periodic intervals along the length of the laser. Such a laser is shown in FIG. 5 of the Kogelnik et al patent. The net effect of the current mask is to produce a periodic gain variation within the semiconductor laser. A new type of three terminal device was disclosed at the International Electron uevices Meeting in Washington, D. C., 1979 by scientists from the Massachusetts Institute of Technology, Lincoln Laboratory, Lexington, MA. This device is shown and described on page 130 of electronics, December 6, 1979. As shown in Electronics, the device is a permeable base transistor wnose base consists of a layer of tungsten that has been patterned into a 3200 Å period grating layer which layer is epitaxially embedded in a single crystal of n-type gallium arsenide. This transistor wherein the base is a grid-like metallic structure is said to provide many advantages over
gallium arsenide field effect transistors. This transistor, however, is not a laser, and the present invention relates to the recognition of the utility, and the means for incorporating, the new technology in laser devices.
Summary of the Invention
In accordance with the present invention, a grid-like conductive current mask is fabricated between the active region in a semiconductor laser and one of the electrodes between which the pump current flows. Changing the potential that is provided to this conductive current mask can regulate the light output from the semiconductor laser and also provide a means for adjusting the output wavelength in those lasers where the conductive current mask is sufficiently close to the active region to cause it to function as a distributed feedback laser. For maximum regulation, the conductive current mask is placed in a lightly doped buffer layer so that maximum modulation of the depletion depth around the current is obtained. Doping of this buffer layer must be sufficiently great, however, so that sufficient current to operate the laser is available.
In accordance with one embodiment of the present invention a semiconductor laser structure is etched in order to establish a pattern of grooves or notches over the active region along the length of the laser structure. A conductive terminal is deposited over the top parts of the notches that are not affected by the etching, and a conductive terminal is deposited over the entire bottom of the semiconductor laser structure thereby forming the two terminals through which the pump current flows. A third conductive layer is deposited at the bottoms of the grooves or notches to form the gate electrode which controls the pump current. In accordance witn the second embodiment a cladding region is epitaxially grown over the active region, and growth is terminated so that a conductive
metallic grid can ioe deposited over the cladding layer. Epitaxial growth is then resumed and a top buffer layer of low conductivity is grown over the grid structure followed by a cap and contact layer. In this second embodiment, the grid structure is totally embedded within the cladding and top buffer layers, and contact to the grid structure is made by grooves that are etched along the length of the semiconductor laser. brief Description of the Drawing FIG. 1 is a pictorial drawing of a section of a semiconductor laser constructed in accordance with the present invention;.
FIG. 2 is a cross sectional diagram of the device illustrated in FIG. 1; FIGS. 3 and 4 are top and end views, respectively, of a second embodiment constructed in accordance with the present invention; and
FIG. 5 is a cross sectional diagram of the device illustrated in FIGS. 3 and 4. Detailed Description
One embodiment of the present invention is illustrated in the pictorial view shown in FIG. 1. A cross sectional view designated by the numeral 2 in FIG. 1 is shown in FIG. 2. The features and layers of this device are exaggerated in order to illustrate the construction.
The device as shown is constructed, for example, by growing an epitaxial n-type buffer layer 11 of indium phosphide on an n+ substrate 10 of indium phosphide. This is then followed by an epitaxial growth of a quaternary layer 12 having a composition which will lase at the chosen wavelength. For tne materials system used in this device using indium, gallium, arsenic and phosphorous, a wavelength of 1.3μm would be typical. The active quaternary layer 12 is then covered by a cladding layer 13 of p-tyρe indium phosphide which is grown relatively thick (about 2.5μm) for the chosen wavelength of 1.3μm . The cladding layer is then followed by the growth of a contact
layer 14 of high conductivity p-type indium phosphide or quaternary material. The doping of cladding layer 13 should be sufficiently light so that the grid structure to be described hereinafter will be able to pinch off a channel width of about Λ/2 where Λ is the period of the grid structure. However, the doping must be sufficiently high to carry the necessary currrent to operate the laser. The entire top structure of the epitaxially grown device is then covered with a silicon nitride layer 15. Silicon nitride layer 15 is then coated with a photoresist, and the photoresist is exposed to produce a pattern which will permit etching of the layers in the indented areas of the device illustrated by the pictorial view in FIG. 1. This etching is initiated by a reactive ion etch using CHF3 or a CF4+O2 mixture in a plasma etch geometry to cut through the silicon nitride layer. This step is then followed by a reactive ion etch using pure Cl2 in order to cut away all of contact layer 14 and approximately 1μm of tne indium phosphide cladding layer 13 in the areas being etched. In order to alleviate problems that might result when using a photoresist, one could also use a titanium and aluminum mask over the silicon nitride and Cl2 + O2 for a reactive ion etch of the indium phosphide cap layer. At this point in time, the device will begin to resemble the one illustrated in FIG. 1. A 5 second immersion of the device in concentrated hydrochloric acid is used to smooth the InP and slightly undercut the silicon nitride layer in order to produce an overhang of the silicon nitride layer of approximately 0.2μm as illustrated in FIG. 1. This overhang is desirable in order to prevent the material which is deposited in the following step from adhering to the sidewails of the posts in the corrugated pattern produced during the reactive ion etch. Alternatively, if the corregation period Λ is sufficiently large, the etching may be wholly accomplished with HCl alone. It is important that the mask be oriented as shown
in FIG. 1 so that the side walls of the corrugated pattern be (01 ) or (011) crystal planes after HC1 etching.
A material that, will form a good blocking contact with the cladding material is then deposited over the top surface of the device in order to create a gating electrode 16 which exists not only in the bottom-most regions of the notches that are created but also extends out over portion 26 of the cladding region which is exposed at the front edge of the device illustrated in FIG. 1. In this context, a Dlocking contact is defined as one which will cause a depletion of the surrounding material when the appropriate bias is applied. This action can be provided by reverse biased p-n, Schottky barrier, or metal- insulator-semiconductor junctions. In the embodiment illustrated in FIG. 1 and 2, where the cladding layer is p-tyρe Inf, the gating electrode can be fabricated from a gold-germanium-alloy. Firing at a suitably elevated temperature may be used to improve the blocking quality of the gate. The gold-germanium that is deposited over the mask covering tne ridges is then removed by using the appropriate resist stripper to remove the photoresist mask, or by using sodium hydroxide to remove a titanium+ aluminum mask.
A second resist pattern is then formed over the device to create windows in the top posts of the corrugated pattern. A plasma etch can be used to cut through the silicon nitride in these windows and a gold-zinc layer 17 can then be deposited in the windows and fired if necessary in order to produce a good ohmic contact with the high conductivity contact layer 14. A third mask pattern using a photoresist material is tnen utilized to create a chromium gold layer 18 which not only makes contact with the windowed layers 17 but also extends out over the rear portion of the device shown in FIG. 1 in order to provide an extended contact to the anode of the diode which has been constructed.
The devices on a single wafer can then be separated either by sawing or by using a bromine-methanol solution. It should be apparent to those skilled in the art that end mirrors can then be formed by cleaving or by a suitable etching procedure in those cases where the device may be part of a more complicated integrated optics structure.
If the spacing d is made sufficiently small ( ~ λ) and the period is chosen to satisfy the Bragg condition, distributed feedback action will occur. Then the output surfaces would not have to be mirrors, and they could be AR coated to prevent unwanted reflection. The device shown in FIGS. 1 and 2 is utilized by applying a positive potential to anode contact 18 and a negative potential to the cathode contact 19 which is a gold-zinc contact that has been deposited over the entire bottom surface of substrate 10. Application of a negative potential to the gating electrode 16 then creates depletion regions of the type shown and designated in FIG. 2 as regions 21. These depletion regions can be utilized to pinch off current tnat is flowing from anode 18 before this current passes through the active layer 12 in a manner illustrated by the current lines 22 shown in FIG. 2. Hence gating electrode is not only a current mask but is a current mask that can change its degree of effectiveness depending on the potential that is applied.
A second embodiment of the present invention can he constructed to provide a device of the type illustrated in FIGS. 3, 4 and 5. FIGS. 3 and 4 are top and side views of the device, and FIG. 5 is a cross sectional view of the device through a plane designated by the numeral 5 in FIG. 3. This embodiment is constructed by first growing a ρ-tyρe buffer layer 41 of indium phosphide on p+ substrate 40 of indium phosphide. This growth is followed by an undoped active quaternary layer 42 and an n-type cladding layer 43 of indium phosphide. These layers are identical to those which are grown for a typical double
neterostructure laser fabricated on a p-type substrate except the n+ contact layer normally grown on a double heterostructure is left off. For distributed feedback action, cladding layer 43 is grown to a thickness (d) that is sufficiently small to permit the evanescent field of the optical mode to reach its top surface.
The growth of layers 41, 42 and 43 illustratively involves the preparation of a (100) cadmium or zinc doped substrate with a Bromine-methanol polish-etch. The substrate is inserted into the liquid phase epitaxial system and heated to approximately 650 degrees C and permitted to cool .at a rate of about 0.5 degrees C per minute, while melts suitable for growing the first set of layers shown in FIG. 5 are alternately slid into position on the substrate.
After the cladding layer 43 has been grown, the device is removed from the liquid phase epitaxial system and the cladding layer 43 is immediately coated with a photoresist and exposed with the desired grating period, Λ . If distributed feedback operation is desired, the period, Λ , is chosen to provide Bragg reflection at the laser wavelength.
At this point, a tungsten or conductive carbon gating electrode 48 may be evaporated over the photoresist pattern. If desired, shallow grooves may first be formed by plasma etching in order .to allow the tungsten or carbon gating electrode 48 to be recessed into the surface of the n-type cladding layer 43. This recessing can provide a planar surface for the growths which are to follow. After solvent cleaning, the entire substrate is then placed into the liquid phase epitaxial system and a lightly doped n-type top buffer layer 44 of indium phosphide is grown over the gating electrode 48. This top buffer layer 44 is followed by an n-type cap layer 45 of indium phosphide and a heavily doped quaternary contact layer 46. Contact is made to the gating electrode 48 by etching channels along the entire length of the device as
illustrated in FIGS. 3 and 4. A cathode electrode 47 of gold and tin is then deposited over the entire length of the device, and a gold-zinc anode electrode 49 is formed over the entire bottom surface of substrate 40. By choosing the electrical bias applied to gating electrodes 16 and 48 in either of the described embodiments and selecting various layer thicknesses and dopings during growth, several modes of operation are possible for both embodiments. If the separation d between the gating electrode 16 or 48 and the active layer is large, that is, d is much greater than the operating wavelength, there will be no distributed feedback action and the devices will function only as modulated Fabry-Perot lasers with end mirrors required. The gating electrode under these circumstances can be utilized to modulate the level of the laser output, riigh modulation efficiency and speed will be provided through the transistor action of the gating electrode. if, however, tne gating electrode is brought to within a wavelength of the active quaternary layer and the period Λ chosen to meet the Bragg criteria, distributed feedback action will be added by the resulting spatially periodic gain. In the latter case all of the reflections required can be provided by the gating electrode, and the enα mirrors are no longer necessary, thereby permitting the αevice to be incorporated into a complex integrated optics structure. Wavelength control is expected to be possible while the laser provides a constant output by simultaneously varying the anode bias and the voltage applied to the gating electrode. Again, high modulation efficiency and speed is realized by modulating only the gate electrode.
Wnat has been described hereinabove are two illustrative embodiments of the present invention. The first describes a p on n configuration while the second describes an n on p configuration. Two more embodiments are possible by interchanging n for p and vice-versa in
both cases, provided only that the associated contacting materials are also changed in accordance with the layer to which they are applied.
Claims
1. A semiconductor laser having an active region (12) and at least two electrodes (18, 19) between which a potential can be established to cause a pump current to flow through said active region, CHARACTERIZED IN THAT said semiconductor laser includes a gating electrode (16) fabricated from a conductive material and disposed between one of said two electrodes and said active regi on.
2. A semiconductor laser as defined in claim 1 wherein said gating electrode (Fig.5, 48) is fabricated as a single layered structure positioned In a lightly doped layer (44) proximate to said active region.
3. A semiconductor laser as defined in claim 1 wherein said gating electrode (16) is fabricated in the bottom regions of a corrugated structure created along the length of said semiconductor laser.
4. A semiconductor laser as defined in claim 1 wherein said corrugated structure has a period, A , which is chosen to provide Bragg reflection.
5. A semiconductor laser comprising a substrate (10) of III-V semiconductor material having a first electrode (19) fabricated on one of its surfaces and a plurality of epitaxial layers (11, 12, 13, 14) grown on an opposite surface, one (12) of said plurality of layers including an active region which generates light in response to a pumping current, a second (18) electrode structure fabricated on said plurality of epitaxial layers such that a potential can be applied between said first and second electrodes to develop a pumping current which flows through said active region
CHARACTERIZED IN THAT said semiconductor laser further includes a current mask (16) fabricated of conductive material and positioned between said second electrode and said active region.
6. A semiconductor laser as defined in claim 5 wherein said plurality of epitaxial layers includes a lightly doped layer (Fig. 5, 44) proximate to said active region and said conductive current mask is disposed within said lightly doped epitaxial layer.
7. A semiconductor laser as defined in claim 5 wherein said plurality of epitaxial layers is notched to create a corrugated pattern, and said conductive current mask is fabricated in the lower regions of said corrugated pattern.
8. A semiconductor laser as defined in claim 7 wherein said corrugated pattern is fabricated to have a period, Λ , which causes the conductive current mask to provide Bragg reflection.
9. A semiconductor laser comprising a substrate
(10) of one type conductivity having a first (19) electrode means fabricated on one surface and a first (11) epitaxial layer of said one type conductivity grown on an opposite surface of said substrate, an undoped active layer (12) epitaxiaily grown on said first epitaxial layer, a plurality of cladding layers (13, 14) of opposite conductivity grown on said active layer, and a second (18) electrode means fabricated on the top surface of said cladding layers, said first and second electrode means and said active region being oriented such that a potential which is applied between said first and second electrode means causes a pumping current to flow through said active layer
CHARACTERIZED IN THAT said plurality of cladding layers includes a grid-like conductive current mask to which a potential can be applied to regulate the flow of said pumping current.
10. A semiconductor laser as defined in claim 9 wherein said plurality of cladαing layers includes a lightly doped layer, (Fig.5, 44) and said grid-like conductive current mask is disposed within said lightly doped cladding layer.
11. A semiconductor laser as defined in claim 9 wherein a notched pattern is created in said plurality of cladding layers along the length of said active layer, said second electrode means is positioned at the topmost regions of said notched pattern and said grid-liκe conductive current mask is positioned at the bottom regions of said notched pattern.
12. A semiconductor laser as defined in claim 11 wherein said notched pattern is fabricated with a period, Λ , such that said grid-like conductive current mask provides Bragg reflection.
13. A semiconductor laser as defined in claim 11 wherein said grid-like conductive current mask is fabricated from materials that form a blocking contact with the surrounding cladding layer.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE8282902872T DE3280027D1 (en) | 1981-09-28 | 1982-08-30 | Semiconductor laser with conductive current mask |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/306,287 US4445218A (en) | 1981-09-28 | 1981-09-28 | Semiconductor laser with conductive current mask |
US306,287810928 | 1981-09-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1983001155A1 true WO1983001155A1 (en) | 1983-03-31 |
Family
ID=23184626
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1982/001171 WO1983001155A1 (en) | 1981-09-28 | 1982-08-30 | Semiconductor laser with conductive current mask |
Country Status (8)
Country | Link |
---|---|
US (1) | US4445218A (en) |
EP (1) | EP0089980B1 (en) |
JP (1) | JPS58501567A (en) |
CA (1) | CA1194971A (en) |
DE (1) | DE3280027D1 (en) |
GB (1) | GB2106706B (en) |
IT (1) | IT1152641B (en) |
WO (1) | WO1983001155A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5554061A (en) * | 1994-09-30 | 1996-09-10 | Electronics & Telecommunications Research Institute | Method for making a vertical resonant surface-emitting micro-laser |
Families Citing this family (32)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2525033B1 (en) * | 1982-04-08 | 1986-01-17 | Bouadma Noureddine | SEMICONDUCTOR LASER HAVING SEVERAL INDEPENDENT WAVELENGTHS AND ITS MANUFACTURING METHOD |
US4679199A (en) * | 1985-09-23 | 1987-07-07 | Gte Laboratories Incorporated | High power InGaAsP/InP semiconductor laser with low-doped active layer and very low series resistance |
JP2539368B2 (en) * | 1985-12-20 | 1996-10-02 | 株式会社日立製作所 | Semiconductor laser device |
JPS62257783A (en) * | 1986-04-30 | 1987-11-10 | Sharp Corp | Semiconductor laser element |
FR2598862B1 (en) * | 1986-05-16 | 1994-04-08 | Bouley Jean Claude | SEMICONDUCTOR LASER WITH DISTRIBUTED REACTION AND CONTINUOUSLY TUNABLE WAVELENGTH. |
DE3713045A1 (en) * | 1987-04-16 | 1988-10-27 | Siemens Ag | Method for producing a laser diode having a buried active layer and lateral current limiting, and a laser diode having a buried active layer and lateral current limiting |
US5224115A (en) * | 1991-07-17 | 1993-06-29 | The United States Of America As Represented By The Secretary Of The Air Force | Distributed feedback laser implemented using an active lateral grating |
JP2705409B2 (en) * | 1991-11-21 | 1998-01-28 | 三菱電機株式会社 | Semiconductor distributed feedback laser device |
US5338394A (en) * | 1992-05-01 | 1994-08-16 | Alliedsignal Inc. | Method for etching indium based III-V compound semiconductors |
JP3204474B2 (en) * | 1993-03-01 | 2001-09-04 | キヤノン株式会社 | Gain-coupled distributed feedback semiconductor laser and its fabrication method |
US5509093A (en) * | 1993-10-13 | 1996-04-16 | Micron Optics, Inc. | Temperature compensated fiber fabry-perot filters |
FR2713350B1 (en) * | 1993-12-06 | 1995-12-29 | Franck Delorme | Optical component with a plurality of bragg gratings and method for manufacturing this component. |
FR2715251B1 (en) * | 1994-01-20 | 1996-04-05 | Christophe Kazmierski | Semiconductor structure with virtual diffraction grating. |
FR2716303B1 (en) * | 1994-02-11 | 1996-04-05 | Franck Delorme | Wavelength tunable distributed Bragg reflector laser with selectively activated virtual diffraction gratings. |
US6291839B1 (en) | 1998-09-11 | 2001-09-18 | Lulileds Lighting, U.S. Llc | Light emitting device having a finely-patterned reflective contact |
US6922426B2 (en) | 2001-12-20 | 2005-07-26 | Finisar Corporation | Vertical cavity surface emitting laser including indium in the active region |
US20030219917A1 (en) * | 1998-12-21 | 2003-11-27 | Johnson Ralph H. | System and method using migration enhanced epitaxy for flattening active layers and the mechanical stabilization of quantum wells associated with vertical cavity surface emitting lasers |
US7167495B2 (en) * | 1998-12-21 | 2007-01-23 | Finisar Corporation | Use of GaAs extended barrier layers between active regions containing nitrogen and AlGaAs confining layers |
US7435660B2 (en) * | 1998-12-21 | 2008-10-14 | Finisar Corporation | Migration enhanced epitaxy fabrication of active regions having quantum wells |
US7095770B2 (en) | 2001-12-20 | 2006-08-22 | Finisar Corporation | Vertical cavity surface emitting laser including indium, antimony and nitrogen in the active region |
US7408964B2 (en) | 2001-12-20 | 2008-08-05 | Finisar Corporation | Vertical cavity surface emitting laser including indium and nitrogen in the active region |
US7257143B2 (en) * | 1998-12-21 | 2007-08-14 | Finisar Corporation | Multicomponent barrier layers in quantum well active regions to enhance confinement and speed |
US6975660B2 (en) | 2001-12-27 | 2005-12-13 | Finisar Corporation | Vertical cavity surface emitting laser including indium and antimony in the active region |
US7286585B2 (en) * | 1998-12-21 | 2007-10-23 | Finisar Corporation | Low temperature grown layers with migration enhanced epitaxy adjacent to an InGaAsN(Sb) based active region |
US7058112B2 (en) | 2001-12-27 | 2006-06-06 | Finisar Corporation | Indium free vertical cavity surface emitting laser |
US6822995B2 (en) * | 2002-02-21 | 2004-11-23 | Finisar Corporation | GaAs/AI(Ga)As distributed bragg reflector on InP |
US7295586B2 (en) * | 2002-02-21 | 2007-11-13 | Finisar Corporation | Carbon doped GaAsSb suitable for use in tunnel junctions of long-wavelength VCSELs |
CA2581614A1 (en) * | 2004-10-01 | 2006-04-13 | Finisar Corporation | Vertical cavity surface emitting laser having multiple top-side contacts |
US7860137B2 (en) * | 2004-10-01 | 2010-12-28 | Finisar Corporation | Vertical cavity surface emitting laser with undoped top mirror |
CA2533225C (en) * | 2006-01-19 | 2016-03-22 | Technologies Ltrim Inc. | A tunable semiconductor component provided with a current barrier |
JP5865860B2 (en) * | 2013-03-25 | 2016-02-17 | 株式会社東芝 | Semiconductor device |
DE102020108941B4 (en) * | 2020-03-31 | 2022-05-25 | Ferdinand-Braun-Institut gGmbH, Leibniz- Institut für Höchstfrequenztechnik | Diode laser with reduced beam divergence |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4023993A (en) * | 1974-08-22 | 1977-05-17 | Xerox Corporation | Method of making an electrically pumped solid-state distributed feedback laser |
US4169997A (en) * | 1977-05-06 | 1979-10-02 | Bell Telephone Laboratories, Incorporated | Lateral current confinement in junction lasers |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2420517A1 (en) * | 1974-04-27 | 1975-11-06 | Licentia Gmbh | Opto-electronic semiconductor element - has substrate with deposited semiconductor layers of opposite conductivity with substrate dependent pn-junction |
JPS571912B2 (en) * | 1974-05-31 | 1982-01-13 | ||
US3959808A (en) * | 1974-09-19 | 1976-05-25 | Northern Electric Company Limited | Variable stripe width semiconductor laser |
US4152711A (en) * | 1976-04-01 | 1979-05-01 | Mitsubishi Denki Kabuchiki Kaisha | Semiconductor controlled luminescent device |
JPS52147087A (en) * | 1976-06-01 | 1977-12-07 | Mitsubishi Electric Corp | Semiconductor light emitting display device |
JPS606553B2 (en) * | 1977-08-30 | 1985-02-19 | 富士通株式会社 | semiconductor light emitting device |
US4190813A (en) * | 1977-12-28 | 1980-02-26 | Bell Telephone Laboratories, Incorporated | Strip buried heterostructure laser |
US4236122A (en) * | 1978-04-26 | 1980-11-25 | Bell Telephone Laboratories, Incorporated | Mesa devices fabricated on channeled substrates |
JPS56104488A (en) * | 1980-01-23 | 1981-08-20 | Hitachi Ltd | Semiconductor laser element |
-
1981
- 1981-09-28 US US06/306,287 patent/US4445218A/en not_active Expired - Lifetime
-
1982
- 1982-08-30 DE DE8282902872T patent/DE3280027D1/en not_active Expired
- 1982-08-30 JP JP57502933A patent/JPS58501567A/en active Pending
- 1982-08-30 WO PCT/US1982/001171 patent/WO1983001155A1/en active IP Right Grant
- 1982-08-30 EP EP82902872A patent/EP0089980B1/en not_active Expired
- 1982-08-31 CA CA000410492A patent/CA1194971A/en not_active Expired
- 1982-09-23 GB GB08227184A patent/GB2106706B/en not_active Expired
- 1982-09-24 IT IT23442/82A patent/IT1152641B/en active
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4023993A (en) * | 1974-08-22 | 1977-05-17 | Xerox Corporation | Method of making an electrically pumped solid-state distributed feedback laser |
US4169997A (en) * | 1977-05-06 | 1979-10-02 | Bell Telephone Laboratories, Incorporated | Lateral current confinement in junction lasers |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5554061A (en) * | 1994-09-30 | 1996-09-10 | Electronics & Telecommunications Research Institute | Method for making a vertical resonant surface-emitting micro-laser |
Also Published As
Publication number | Publication date |
---|---|
EP0089980B1 (en) | 1989-11-15 |
EP0089980A1 (en) | 1983-10-05 |
IT1152641B (en) | 1987-01-07 |
GB2106706A (en) | 1983-04-13 |
IT8223442A0 (en) | 1982-09-24 |
GB2106706B (en) | 1985-07-10 |
US4445218A (en) | 1984-04-24 |
CA1194971A (en) | 1985-10-08 |
JPS58501567A (en) | 1983-09-16 |
DE3280027D1 (en) | 1989-12-21 |
EP0089980A4 (en) | 1986-05-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4445218A (en) | Semiconductor laser with conductive current mask | |
EP0233725B1 (en) | Opto-Electronic Device and Method for its Manufacture | |
US4099305A (en) | Fabrication of mesa devices by MBE growth over channeled substrates | |
US4805184A (en) | Ridge waveguide optical devices | |
EP0663710A2 (en) | Optical semiconductor device and method for producing the same | |
EP0064339A1 (en) | Semiconductor laser device | |
US3984262A (en) | Method of making a substrate striped planar laser | |
JPS6384186A (en) | Transverse junction stripe laser | |
EP0033137B1 (en) | Semiconductor laser device | |
US4121179A (en) | Semiconductor injection laser | |
US4948753A (en) | Method of producing stripe-structure semiconductor laser | |
US5801071A (en) | Method for producing semiconductor laser diode | |
US4236122A (en) | Mesa devices fabricated on channeled substrates | |
US5432809A (en) | VCSEL with Al-free cavity region | |
US5170405A (en) | Semiconductor diode laser having smaller beam divergence | |
KR900003844B1 (en) | Semiconductor laser device and manufacturing method thereof | |
US5478774A (en) | Method of fabricating patterned-mirror VCSELs using selective growth | |
EP0205307B1 (en) | Semiconductor laser device | |
US5149670A (en) | Method for producing semiconductor light emitting device | |
JPS6144485A (en) | Semiconductor laser device and manufacture thereof | |
EP0284684A2 (en) | Inverted channel substrate planar semiconductor laser | |
US4416011A (en) | Semiconductor light emitting device | |
JP2940158B2 (en) | Semiconductor laser device | |
JP2990837B2 (en) | Semiconductor laser | |
EP0032401B1 (en) | Semiconductor laser |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Designated state(s): JP |
|
AL | Designated countries for regional patents |
Designated state(s): DE FR NL |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1982902872 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 1982902872 Country of ref document: EP |
|
WWG | Wipo information: grant in national office |
Ref document number: 1982902872 Country of ref document: EP |