| 摘要 |
PROBLEM TO BE SOLVED: To provide a photo detector having rapid responsibility, excellent sensitivity, and little dark current by solving the problem that, in the most prevailing photo detector having such a structure that an p-type light receiving layer is grown on an n-type substrate and then an n-type dopant is selectively diffused via a mask to form a p-type region in the light receiving layer, diffusion is difficult to be controlled and hence the depth of a pn junction varies, causing a variation in sensitivity and dark current, and electrostatic capacitance increases by reverse bias, causing slow responsibility, and in a mesa-type photo detector having such a structure that an n-type light receiving layer and a p-type light receiving layer are epitaxially grown on an n-type substrate and then the periphery is mesa-etched and covered with an SiN and InP films, the dark current increases due to the leakage, causing a poor yield. SOLUTION: On top of an n-type substrate, an n-type buffer layer, an n-type light receiving layer, and a p-type light receiving layer are epitaxially grown. Then, an n-type dopant is heavily introduced into the periphery by diffusion or ion implantation to form an n-type shielding region from the top face to a buffer layer. COPYRIGHT: (C)2005,JPO&NCIPI
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