Method of producing semiconductor laser

Claim 1

A method of producing a semiconductor laser, comprising the steps of: forming a first high resistance clad layer, having a first band gap, on a semi-insulating semiconductor substrate; forming an active layer of a multiquantum well structure, in which quantum wells have a second band gap narrower than said first band gap, on said first clad layer; forming a second high resistance clad layer on said active layer, said second clad layer having a property of a diffusion coefficient of impurities which reduces from the lower portion thereof toward the upper surface thereof, the lower portion of said second clad layer having a third band gap wider than said second band gap; selectively thermally diffusing first impurity atoms into said first clad layer through a first portion of said second clad layer and a first portion of said active layer, so that said first portion of said active layer is disordered and the diffused portions form a first conduction region of a first conductivity type; and selectively thermally diffusing second first impurity atoms into said/clad layer through a second portion of said second clad layer and a second portion of said active layer at a desired distance from said first portion of said active layer, so that said second portion of said active layer is disordered and the diffused portions form a second conduction region of a second conductivity type opposite to that of said first conductivity type.

Claim 2

A method of producing a semiconductor laser, comprising the steps of: forming a first high resistance clad layer, having a first band gap, on a semi-insulating semiconductor substrate; forming an active layer of a multiquantum well structure, in which quantum wells have a second band gap narrower than said first band gap, on said first clad layer; forming a second high resistance clad layer on said active layer, said second clad layer having a property of a diffusion coefficient of impurities which reduces from the lower portion thereof toward the upper surface thereof, the lower portion of said second clad layer having a third band gap wider than said second band gap; selectively thermally diffusing first impurity atoms into said first clad layer through a first portion of said second clad layer and a first portion of said active layer, so that said first portion of said active layer is disordered and the diffused portions form a first conduction region of a first conductivity type; and selectively thermally diffusing second first impurity atoms into said/clad layer through a second portion of said second clad layer and a second portion of said active layer at a desired distance from said first portion of said active layer, so that said second portion of said active layer is disordered and the diffused portions form a second conduction region of a second conductivity type opposite to that of said first conductivity type.

Claim 10

A method according to any preceding claim, wherein the steps of thermal diffusion for impurity atoms are carried out by using a vapor source. wherein the

Claim 11

A method according to any- one of claims 1 to 8, wherein the steps of thermal diffusion for impurity atoms are carried out by using a solid source. wherein the

Claim 12

A method according to any one of claims 1 to 8, wherein thesteps of thermal diffusion for impurity atoms are carried out by ion-implanting said atoms at a shallow depth and carrying out an annealing process to diffuse said implanted atoms.

Claim 13

A method according to any preceding claim, wherein the portions of the diffusion fronts of the first and second conduction regions adjacent to an active region of the active layer form substantially vertical planes.

Claim 14

A method of producing a compound semiconductor laser comprising steps of: forming a first high resistance clad layer of AlGaAs on a semi-insulating GaAs substrate; forming a multiquantum well active layer comprising GaAs wells and AlGaAs barrier layers on said first clad layer ; forming a second high resistance clad layer of AlGaAs on said active layer, the Al content of said second clad layer being decreased toward an upper portion from a lower portion thereof; forming a cap layer of undoped GaAs on said second clad layer; selectively removing said cap layer; selectively thermally diffusing P-type impurity atoms into said first clad layer through said second clad layer and said active layer to form an N-type region; selectively thermally diffusing N-type impurity atoms into said first clad layer through said second clad layer and said.active layer to form an N-type region; selectively forming a P-electrode on said cap layer; alloying said P-electrode to cause an electrical connection thereof with said P-type region; selectively forming an N-electrode on said cap layer; and alloying said N-electrode to cause an electrical connection thereof with said N-type region.

Claim 15

A method of producing a compound semiconductor laser comprising steps of: forming a first high resistance clad layer of AlGaAs on a semi-insulating GaAs substrate; forming a multiquantum well active layer comprising GaAs wells and AlGaAs barrier layers on said first clad layer ; forming a second high resistance clad layer of AlGaAs on said active layer, the Al content of said second clad layer being decreased toward an upper portion from a lower portion thereof; forming a cap layer of undoped GaAs on said second clad layer; selectively removing said cap layer; selectively thermally diffusing P-type impurity atoms into said first clad layer through said second clad layer and said active layer to form an N-type region; selectively thermally diffusing N-type impurity atoms into said first clad layer through said second clad layer and said.active layer to form an N-type region; selectively forming a P-electrode on said cap layer; alloying said P-electrode to cause an electrical connection thereof with said P-type region; selectively forming an N-electrode on said cap layer; and alloying said N-electrode to cause an electrical connection thereof with said N-type region.