Matsushita Electronics Corporation

Katuya Ishikawa

Genshu Fuse

A dielectric film is formed on a P type silicon substrate. Then a specified resist pattern is formed on the dielectric film. Using this resist pattern as the mask, a phosphorus ion beam is implanted. Then, removing the resist pattern, heat treatment is given. By this heat treatment, a photo diode is formed in a depth of about 1 .mu.m. A specified resist pattern is formed again on the dielectric film. Using this resist pattern as the mask, boron ions are implanted. Thus, a channel stopper region is formed. Afterwards, removing the resist pattern, the dielectric film is removed. Again, a dielectric film is formed on the silicon substrate. Later, a stacked oxide film is formed in the other regions than the region for forming the photo diode on the dielectric film. Using the stacked oxide film as the mask, a boron ion beam is implanted. When operated in such conditions, a P type diffusion layer of opposite conductive type of photo diode was formed on the surface of the photo diode, and the leak current in the photo diode becomes low. Consecutively, a fluorine ion beam is implanted on the entire surface of the silicon substrate. Thus, on the surface of the photo diode and on the P type diffusion layer, a diffusion layer by fluorine is provided. Thus, to suppress the leak current generated in the photo diode, the interface state density is lowered, while the level of implantation defects may be suppressed at the same time.

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Kyoto, Japan

Katuya Ishikawa