Matsushita Electric Industrial Co., Ltd.

Takao Shibutani

Kunio Itoh

Hirokazu Shimizu

Ken Hamada

Masahiro Kume

Masaru Wada

Iwao Teramoto

A BTRS (buried Twin-Ridge Substrate) structure laser, wherein an oblong protrusion (10) is provided on a substrate (1) of a first conductivity type and two ridges (9, 9) divided by a groove (31) therebetween are provided on a second layer (2) of a second conductivity type, and thereon plural layers (3, 4, 5, 6) including an active layer (4) are provided is improved to have longer service life such that: the protrusion (10) is shortened so as to have its both ends apart inside cavity facet of the substrate (1), or further by width of each ridge (9, 9) is narrowed at both ends thereof thereby forming narrowed end parts (9', 9'), so that excessive current injection to the active layer near the cavity facet is eliminated.

Buried twin ridge substrate laser

The invention provides a chemical etching method for a semiconductor device, which comprises a step of forming a first layer of Ga.sub.1-x Al.sub.x As (0.ltoreq.x&lt;1) having a surface (100), a step of forming on the first layer a second layer of Ga.sub.1-y Al.sub.y As (0.ltoreq.y&lt;1) having a surface (100), and a step of chemically etching the layers from a level above the second layer and along the direction of &lt;011&gt;. The slope angle of etch face of the second layer depends on the mol fraction y of the second layer, and the slope angle of etch face of the first layer depends on the mol fraction y of the second layer and the mol fraction x of the first layer. These facts are best utilized in the invention so that the etch profile of the first layer may have a desired slope angle. By utilizing this chemical etching method it is possible to produce by chemical etching a semiconductor laser having a flat cavity facet perpendicular to a junction; it is also possible to provide an inner stripe type semiconductor laser having grooves whose side walls are perpendicular.

Method of manufacturing semiconductor device

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Takatsuki, Japan

Takao Shibutani