Monolithic injection laser arrays formed by crystal regrowth techniques

Claim 2

A process for forming a monolithic injection laser array, the steps comprising: cleaning, etching, rinsing, and drying an N+-GaAs substrate; epitaxially growing an orginal growth multilayer double heterostructure GaAlAs laser wafer on said substrate; selectively etching V-grooves in the epitaxial layers down through the optical cavity of the laser; preparing said laser wafer for crystal regrowth; regrowing by crystal regrowth GaAlAs in said V-grooves to optically and electrically isolate each adjacent laser; regrowing by crystal regrowth a heavily doped P.sup.± GaAs cap over all the lasers in the laser array including over said crystal regrowth GaAlAs in said V-grooves; thinning said substrate by lapping; and depositing metal ohmic contacts on said P.sup.± GaAs cap and on the lapped N+-GaAs substrate to provide electrical connections to an external power source.

Claim 3

A process as set forth in claim 1 wherein said cleaning, etching, rinsing, and drying steps are comprised of cleaning in hot trichloroethylene, etching in 5 H 2 SO 4 : 1 H 2 O 2 : 1 H 2 O solution, rinsing in distilled water, and drying with N 2 gas.

Claim 4

A process as set forth in claim 2 wherein said step of epitaxially growing an original growth multilayer double heterostructure is comprised of placing said substrate on a slider in a graphite boat container within a furnace in which said container has a plurality of bins each containing the combination of elements that are epitaxially grown by liquid phase epitaxy as each layer of the plurality of multilayers of said original growth as said substrate is slid under each of said bins wherein air is first pumped out of said furnace and pure hydrogen gas at slightly above atmospheric pressure is flowed over said boat as it is heated to 830° C. and the original growth multilayers are grown as said furnace is cooled at 0.1° C. per minute wherein the thickness of each layer of the original growth multilayers is determined by the time said substrate remains under each bin containing each combination of elements.

Claim 5

A process as set forth in claim 3 wherein said step of selectively etching V-grooves is comprised of coating said laser wafer with a positive photoresist and exposing a pattern of stripes by photolithographic techniques for etching said V-grooves with an etch of from 3 to 8 parts H 2 SO 4 : 1 part H 2 O 2 : 1 part H 2 O by volume with said N+-GaAs substrate at (100) orientation and said V-grooves aligned parallel to the (001) edge wherein said positive photoresist is compatible with said etch.

Claim 6

A process as set forth in claim 4 wherein said step of preparing said laser wafer for crystal regrowth is by cleaning with hot trichloroethylene, etching for 5 seconds in an etch comprised of 5 parts H 2 SO 4 : 1 part H 2 O 2 : 1 part H 2 O by volume, rinsing in distilled water, drying with N 2 gas, and reloading in said furnace within 2 minutes after the drying step.

Claim 7

A process as set forth in claim 5 wherein said steps of regrowing by crystal regrowth techniques GaAlAs in said V-grooves and heavily doped P+-GaAs cap is comprised of reheating said furnace to 830° C. with no temperature overshoot and remain stable within 0.1° C. for at least 30 minutes and then cool said furnace 0.2° C. prior to sliding said laser wafer under said growth solution in which said solution is slightly oversaturated when regrowing step is begun wherein said furnace is cooled at 0.1° C. per minute during the step of regrowing GaAlAs in the V-grooves until said V-grooves are filled and wherein said step of regrowing a heavily doped P+-GaAs cap is continued by sliding said substrate under another bin for growing over all the surface of said laser wafer including over the filled V-grooves by continuing cooling said furnace at 0.1° C. per minute while growing said heavily doped P+-GaAs cap for sufficient time to cover the surface to about 3 microns thick.

Claim 8

A process as set forth in claim 6 wherein said step of epitaxially growing an original growth multilayer double heterostructure is comprised of growing a five layer double heterostructure having a first layer of N±Ga 0 .9 Al 0 .1 As grown to about 2.5 microns thick grown on said N+-GaAs substrate and having second and third active layers that form said optical cavity wherein said second layer is N-Ga 0 .98 Al 0 .02 As grown to about 1.2 microns thick and said third layer is P-GaAs grown to about 0.8 micron thick and a fourth layer of P.sup.± Ga 0 .7 Al 0 .3 As grown to about 1.5 microns thick and a fifth layer of P+-GaAs grown to about 4 microns thick and wherein said step of regrowing by crystal regrowth GaAlAs in said V-grooves is comprised of growing a Ga 0 .6 Al 0 .4 As regrowth in said V-grooves up to the surface.

Claim 9

A process as set forth in claim 6 wherein said step of epitaxially growing an original growth multilayer double heterostructure is comprised of growing a six layer double heterostructure having a first layer of N.sup.± GaAs buffer layer grown to about 4 microns thick and a second layer of N+-Ga 0 .85 Al 0 .15 As grown to about 1 micron thick and having third and fourth active layers that form said optical cavity wherein said third layer is N-Ga 0 .93 Al 0 .07 As grown to about 1.5 microns thick and said fourth layer is P-Ga 0 .95 Al 0 .05 As grown to about 1 micron thick and a fifth layer of P.sup.± Ga 0 .7 Al 0 .3 As grown to about 2 microns thick and a sixth layer of P+-GaAs grown to about 1 micron thick and wherein said step of regrowing by crystal regrowth GaAlAs in said V-grooves is comprised of growing a first regrowth of N-Ga 0 .9 Al 0 .1 As filling about one half of said V-grooves and growing a second regrowth of P-Ga 0 .9 Al 0 .1 As filling the remaining one half of said V-grooves up to the surface wherein said first regrowth is grown up to the P-type fourth layer of said optical cavity.

Claim 10

A monolithic injection laser array grown by the process of claims 7 or 8.

Claim 11

A process for forming a monolithic injection layer array, the steps comprising: cleaning, etching, rinsing, and drying an N + -type Group III-V materials substrate; epitaxially growing an original growth multilayer double heterostructure Group III-V materials laser wafer on said substrate; selectively etching V-grooves in the epitaxial layers down through the optical cavity of the laser; preparing said laser wafer for crystal regrowth; regrowing by crystal regrowth Group III-V materials in said V-grooves to optically and electrically isolate each adjacent laser; regrowing by crystal regrowth a heavily doped P + -type Group III-V materials cap over all the lasers in the laser array including over said crystal regrowth Group III-V materials in said V-grooves; thinning said substrate by lapping; and depositing metal ohmic contacts on said P + -type Group III-V materials cap and on the lapped N + -type Group III-V materials substrate to provide electrical connections to an external power source.

Claim 12

A process for forming a monolithic injection layer array, the steps comprising: cleaning, etching, rinsing, and drying an N + -type Group III-V materials substrate; epitaxially growing an original growth multilayer double heterostructure Group III-V materials laser wafer on said substrate; selectively etching V-grooves in the epitaxial layers down through the optical cavity of the laser; preparing said laser wafer for crystal regrowth; regrowing by crystal regrowth Group III-V materials in said V-grooves to optically and electrically isolate each adjacent laser; regrowing by crystal regrowth a heavily doped P + -type Group III-V materials cap over all the lasers in the laser array including over said crystal regrowth Group III-V materials in said V-grooves; thinning said substrate by lapping; and depositing metal ohmic contacts on said P + -type Group III-V materials cap and on the lapped N + -type Group III-V materials substrate to provide electrical connections to an external power source.

Claim 13

A process for forming a monolithic injection laser array, the steps comprising: cleaning, etching, rinsing, and drying an N + -type Group IV-VI materials substrate; epitaxially growing an original growth multilayer double heterostructure Group IV-VI materials laser wafer on said substrate; selectively etching V-grooves in the epitaxial layers down through the optical cavity of the laser; preparing said laser wafer for crystal regrowth; regrowing by crystal regrowth Group IV-VI materials in said V-grooves to optically and electrically isolate each adjacent laser; regrowing by crystal regrowth a heavily doped P + -type Group IV-VI materials cap over all the lasers in the laser array including over said crystal regrowth Group IV-VI materials in said V-grooves; thinning said substrate by lapping; and depositing metal ohmic contacts on said P + -type Group IV-VI materials cap and on the lapped N + -type Group IV-VI materials substrate to provide electrical connections to an external power source.

Claim 14

A process for forming a monolithic injection laser array, the steps comprising: cleaning, etching, rinsing, and drying an N + -type Group IV-VI materials substrate; epitaxially growing an original growth multilayer double heterostructure Group IV-VI materials laser wafer on said substrate; selectively etching V-grooves in the epitaxial layers down through the optical cavity of the laser; preparing said laser wafer for crystal regrowth; regrowing by crystal regrowth Group IV-VI materials in said V-grooves to optically and electrically isolate each adjacent laser; regrowing by crystal regrowth a heavily doped P + -type Group IV-VI materials cap over all the lasers in the laser array including over said crystal regrowth Group IV-VI materials in said V-grooves; thinning said substrate by lapping; and depositing metal ohmic contacts on said P + -type Group IV-VI materials cap and on the lapped N + -type Group IV-VI materials substrate to provide electrical connections to an external power source.