Method of manufacturing semiconductor device

A chemical etching method for a semi-conductor device comprising:

• a step of forming a first layer of Ga.sub.1-x Al.sub.x As (0.ltoreq.x<1);
• a step of forming, on said first layer, a second layer of Ga.sub.1-y Al.sub.y As (0.ltoreq.y21 1);
• and
• a step of chemically etching the layers, said etching being initiated at a level above said second layer,
• the mol fraction y for said second layer being suitably determined relative to the mol fraction x for said first layer so that the etching profile of the first layer may have a desired slope angle.

A method of manufacturing a semiconductor laser device comprising:

• a step of forming on a semiconductor substrate having a surface (100)
• a first clad layer of Ga.sub.1-x Al.sub.x As (0<x<1),
• an activated layer of Ga.sub.1-y Al.sub.y As (0.ltoreq.y<1),
• a second clad layer of Ga.sub.1-x Al.sub.x As (0<x<1),
• a contact layer of GaAs, and
• a layer of Ga.sub.1-z Al.sub.z As (0<z<1)
• one over another in the order of mention;
• and
• a step of chemically etching the layers downwardly from said layer of Ga.sub.1-z Al.sub.z As and along the direction of <011>to form cavity facet the difference (z-x) between the mol fraction z of said Ga.sub.1-z Al.sub.z As layer and the mol fraction x of said two clad layers being selected between 0 and 0.2 so that the etched cavity facets is made perpendicular.

A method of manufacturing a semiconductor laser device comprising:

• a steps of forming, on a GaAs layer formed on a semiconductor substrate and having a surface (100), a layer of Ga.sub.1-x Al.sub.x As having a mol fraction defined by the relation 0.1<x<0.6;
• a step of chemically etching the layer downwardly from a level above said Ga.sub.1-x Al.sub.x As layer along the direction of <011>, thereby forming grooves bottomed on said semiconductor substrate;
• and
• a step of forming above said grooves a plurality of layers including an active layer.

A chemical etching method for a semiconductor device comprising:

• a step of forming a first layer of Ga.sub.1-x Al.sub.x As (0.ltoreq.x<1);
• a step of forming on said first layer a second layer of Ga.sub.1-y Al.sub.y As (0.ltoreq.y<1);
• and
• a step of chemically etching the layers downwardly from a level above said second layer,
• the slope angle of etching face of said second layer being controlled by the mol fraction y of said second layer,
• the slope angle of etching face of said first layer being controlled by the mol fraction x of said first layer and the mol fraction y of said second layer.

A chemical etching method for a semiconductor device comprising:

• a step of forming a first layer of Ga.sub.1-x Al.sub.x As (0<x<1) having a surface (100);
• a step of forming on said first layer a second layer of GaAs having a surface (100);
• a step of forming on said second layer a third layer of Ga.sub.1-z Al.sub.z As (0<z<1);
• and
• a step of chemically etching the layers downwardly from said third layer and along the direction of <011>,
• the slope angle of etch face of said first layer being controlled by controlling the difference (z-x) between the mol fraction z of said third layer and the mol fraction x of said first layer.