Hamamatsu-Photonics K.k.

Hiroyasu Nakamura

Mikio Kyomasu

Masanori Sahara

Kenichi Okajima

This invention relates to a monolithic IC having a PIN photodiode and an n-p-n bipolar transistor formed on a single semiconductor (silicon) substrate. In fabricating such IC, it is important to electrically isolate the photodiode and the bipolar transistor. In addition it is necessary to make the surface of the substrate flat. According to this invention, the inter-device isolation between the above-described two devices is attained by forming two epitaxial layers on the silicon substrate, forming trenches in the layers, and burying silicon dioxide in the trenches. In the monolithic IC according to this invention wiring capacity is small, and high-speed performance becomes possible. A p-type buried-layer is formed below the bipolar transistor to thereby prevent punch through between the bipolar transistor and other devices. Also this invention provides the process for fabricating a planar type bipolar transistor suitable to fabricate the monolithic IC and also provides a PIN photodiode of a new structure.

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Hamamatsu, Japan

Hiroyasu Nakamura