Mitsubishi Denki Kabushiki Kaisha

Tatuya Kimura

Tadashi Kimura

Hitoshi Tada

Nobuaki Kaneno

Seiji Ochi

Kenzo Mori

Yoshitatu Kawama

Yuji Okura

A semiconductor device includes a III-V compound semiconductor layer including two or more Group III elements and containing dopant impurities, including a spontaneous superlattice, and having a stripe shape with two ends, and electrodes disposed on the ends of the stripe shaped semiconductor layer to form a resistor element. Because of the spontaneous superlattice, electrons are one-dimensionally confined within the III-V compound semiconductor layer, i.e., the electrons flow easier in the direction perpendicular to the periodic direction of the spontaneous superlattice than in the direction parallel to it, resulting in anisotropic electrical resistivity. Therefore, the orientation of the resistor element with respect to the periodic direction of the spontaneous superlattice becomes another factor in determining the resistance of the resistor element. In particular, resistances of the resistor elements of identical stripe shape can be made considerably different from each other, if one is perpendicular to the periodic direction of the spontaneous superlattice and another is parallel to it.

Semiconductor device including doped spontaneously formed superlattice

A semiconductor device includes a III-V compound semiconductor layer including two or more Group III elements and containing dopant impurities, including a spontaneous superlattice, and having a stripe shape with two ends, and electrodes disposed on the ends of the stripe shaped semiconductor layer to form a resistor element. Because of the spontaneous superlattice, electrons are one-dimensionally confined within the III-V compound semiconductor layer, i.e., the electrons flow easier in the direction perpendicular to the periodic direction of the spontaneous superlattice than in the direction parallel to it, resulting in anisotropic of electrical resistivity. Therefore, the orientation of the resistor element with respect to the periodic direction of the spontaneous superlattice becomes another factor in determining the resistance of the resistor element. In particular, resistances of the resistor elements of identical stripe shape can be made considerably different from each other, if one is perpendicular to the periodic direction of the spontaneous superlattice and another is parallel to it.

A method for fabricating a semiconductor laser includes forming a double heterojunction structure on a first conductivity type semiconductor substrate; forming the double heterojunction structure into a stripe mesa shape by selective etching; successively growing a first conductivity type layer, a second conductivity type current blocking layer, and a first conductivity type current blocking layer on opposite sides of the mesa to embed the mesa; and adding an impurity from a surface of the first conductivity type current blocking layer to form impurity doped regions that electrically separate the second conductivity type current blocking layer from an upper part of the mesa at opposite sides of the mesa.

Method of making semiconductor laser

A semiconductor laser includes a first conductivity type semiconductor substrate; a double-heterojunction structure including a first conductivity type cladding layer, an active layer, and a second conductivity type cladding layer successively disposed on the semiconductor substrate; two parallel stripe grooves forming the double-heterojunction structure in a mesa shape; a first conductivity type mesa embedding layer, a second conductivity type current blocking layer, and a first conductivity type current blocking layer successively disposed on the semiconductor substrate and contacting opposite sides of the mesa; and impurity doped regions formed by adding an impurity through the surface of the first conductivity type current blocking layer. The impurity doped regions electrically separate an upper part of the mesa from the second conductivity type current blocking layer at opposite sides of the mesa. Since the second conductivity type current blocking layer is not in contact with the mesa structure, no leakage current path is formed in the laser structure.

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Itami, Japan

Tatuya Kimura