Kabushiki Kaisha Toshiba

Yoshio Yamamoto

Kaoru Nakagawa

Takahiro Ito

Bunshiro Yamaki

Nobutaka Matsuoka

Shigeru Moriyama

Kinzo Tao

In a high-frequency amplifying semiconductor device in which a MOS field effect transistor and a bipolar transistor are formed within the same wafer and a source electrode of the MOS field effect transistor is connected to a lead frame by a bonding wire, use is made of a wafer for fabricating the MOS field effect transistor and the bipolar transistor, in which on a semiconductor substrate of P++ type is formed a first epitaxial layer of P or P- type, a buried layer of N+ type is formed in the first epitaxial layer of the first conductivity type and a second epitaxial layer of P type is formed on the buried layer and the first epitaxial layer. The use of such a wafer, which has no P- type Si substrate, allows the source resistance of the MOS field effect transistor to be decreased. The high-frequency amplifying semiconductor device is improved in high-frequency gain and NF.

High-frequency amplifying semiconductor device

A semiconductor device comprises a semiconductor substrate in which a plurality of semiconductor regions are formed, a front surface electrode in contact with the region, and a back surface electrode consisting of a gold alloy layer and a silver layer. After formation of the front surface electrode, the back side of the substrate is polished. Then, the gold alloy layer and the silver layer are formed in succession on the polished back surface of the substrate.

Method of producing a semiconductor device provided with front and back

The present semiconductor device comprises a first semiconductor substrate, an oxide film formed on the substrate and a second semiconductor substrate bonded to the oxide film. In particular, the semiconductor substrate further has a monocrystalline silicon layer which is formed by an epitaxial growth method on the second semiconductor substrate. Circuit elements are formed within the monocrystalline silicon layer.

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Yokohama, Japan

Yoshio Yamamoto