US 5,395,792 AGranted

Process for fabricating a semiconductor laser device

AssigneeRohm Co., Ltd.

InventorsKatsuhiko Ikawa, Hiroshi Matagi

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Abstract

There is provided a process for fabricating a highly reliable semiconductor laser device operable at a low current with an increased yield, which process includes the steps of: (a) forming a lower clad layer on a semiconductor substrate; (b) forming an active layer of a material larger in refractive index and smaller in forbidden band width than the lower clad layer; (c) forming a first upper clad layer of a material smaller in refractive index and larger in forbidden band width than the active layer; (d) forming an etch stop layer made of GaAs on the first upper clad layer; (e) forming a current-blocking layer of a material smaller in refractive index and larger in forbidden band width than the first upper clad layer; (f) forming a stripe cavity by etching at least a portion of the current-blocking layer down to the etch stop layer; (g) evaporating the etch stop layer remaining in the stripe cavity; (h) forming a second upper clad layer of a material smaller in refractive index and larger in forbidden band width than the active layer while larger in refractive index and smaller in forbidden band width than the current-blocking layer; and (i) forming a contact layer of a material larger in refractive index and smaller in forbidden band width than the active layer.

Claims7

Dependent claims

A process for fabricating a semiconductor laser device, comprising the steps of:

(a) forming a lower clad layer of a first conductivity type on a semiconductor substrate of the first conductivity type;
(b) forming an active layer on the lower clad layer, the active layer being made of a material larger in refractive index and smaller in forbidden band width than the lower clad layer;
(c) forming a first upper clad layer of a second conductivity type on the active layer, the first upper clad layer being made of a material smaller in refractive index and larger in forbidden band width than the active layer;
(d) forming an etch stop layer made of GaAs on the first upper clad layer;
(e) forming a current-blocking layer of the first conductivity type on the etch stop layer, the current-blocking layer being made of a material smaller in refractive index and larger in forbidden band width than the first upper clad layer;
(f) forming a stripe cavity by etching at least a portion of the current-blocking layer down to the etch stop layer;
(g) evaporating the etch stop layer remaining in the stripe cavity;
(h) forming a second upper clad layer of the second conductivity type on the current blocking layer and the stripe cavity, the second upper clad layer being made of a material smaller in refractive index and larger in forbidden band width than the active layer while larger in refractive index and smaller in forbidden band width than the current-blocking layer;
and
(i) forming a contact layer of the second conductivity type on the second upper clad layer, the contact layer being made of a material larger in refractive index and smaller in forbidden band width than the active layer.

7 more elements

Dependencies are inferred from the claim text.