Method for producing an optical semiconductor device having a carrier injection path or an electric-field applying path

A method for producing an optical semiconductor device comprising the steps of:

• forming a first type conductivity layer, a first main layer, which has any one of an undoped type, a first type conductivity and a second type conductivity, and a second type conductivity layer on a substrate in this order;
• forming a contact groove by etching said formed layers down to said first type conductivity layer;
• forming a ridge by making etched grooves extending down to at least said first main layer in both sides of a portion in which said ridge is formed,
• wherein a cross section of one of said etched grooves for forming said ridge, which is nearer to said contact groove, has a reverse trapezoid shape, and said etched groove has a bottom surface and slanting surfaces in both sides of the bottom surface and the other of said etched grooves has at least a slanting surface, and a cross section of said ridge has a trapezoid shape and said ridge has an upper surface and slanting surfaces in both sides of the upper surface, and one of the slanting surfaces of said etched groove nearer to said contact groove and one of the slanting surfaces of said ridge are the same surface, and the slanting surface of said other etched groove and the other slanting surface of said ridge are the same surface;
• and
• performing a regrowth on said ridge, etched grooves and contact groove using an amphi-conductivity impurity as a dopant, so that a first type conductivity portion is grown on at least a portion, extending down to the first type conductivity layer, of the contact groove, and the slanting surfaces of the etched grooves and the ridge, and a second type conductivity portion is grown on the upper surface of the ridge and the bottom surface of the etched groove,
• wherein said first type conductivity layer and a first portion of the first type conductivity portion grown on the portion, extending down to the first type conductivity layer, of the contact groove act as one of a first injection path of one of electrons and holes and first means for applying an electric field to the first main layer, and said second type conductivity layer and a second portion of the second type conductivity portion grown on the upper surface of the ridge act as one of a second injection path of one of electrons and holes and second means for applying an electric field to the first main layer which cooperates with the first means to apply the electric field across the first main layer.

A method for producing an optical semiconductor device comprising the steps of:

• forming a) a first type conductivity layer, b) a first main layer, which has any one of an undoped type, a first type conductivity and a second type conductivity, and c) a second type conductivity layer on a substrate in this order;
• forming a contact groove by etching said formed layers down to said first type conductivity layer;
• forming a ridge by making two etched grooves extending down to at least said first main layer in both sides of a portion in which said ridge is formed,
• wherein a surface on which a first type conductivity portion is grown by performing a growth using an amphi-conductivity impurity as a dopant, is exposed on side portions of the ridge formed by said two etched grooves and a portion, extending down to the first type conductivity layer of the contact groove, and a surface on which a second type conductivity portion is grown by performing a growth using an amphi-conductivity impurity as a dopant is exposed on at least one portion between the contact groove and the ridge and an upper portion of the ridge,
• performing a regrowth using an amphi-conductivity impurity as a dopant, so that the first type conductivity portion is grown on the portion extending down to the first type conductivity layer of the contact groove and the side portions of the ridge, and a second type conductivity portion is grown on at least the one portion between the contact groove and the ridge and the upper portion of the ridge,
• wherein said first type conductivity layer and the portion extending down to the first type conductivity layer of the contact groove act as one of a first injection path of one of electrons and holes and first means for applying an electric field to the first main layer, and said second type conductivity layer and the second type conductivity portion grown on the upper portion of the ridge act as one of a second injection path of one of electrons and holes and second means for applying an electric field to the first main layer which cooperates with the first means to apply the electric field across the first main layer.