OPTICAL SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING SAME

摘要

An optical semiconductor device is provided with a low impurity concentration n-type epitaxial layer (second epitaxial layer) (24) formed on a low concentration p-type silicon substrate (1); a p-type low impurity concentration anode layer (first diffusion layer)(25) selectively formed in the n-type epitaxial layer (24) by ion implantation or the like; an n-type high concentration cathode layer (second diffusion layer) (9) formed on the anode layer (25); a light receiving element (2) constituted by the anode layer (25) and the cathode layer (9); and a transistor (3) formed on the n-type epitaxial layer (24). A photodiode having the high speed and high light receiving sensitivity for short wavelength light and a high speed transistor can be mixedly mounted on the same semiconductor substrate.