Kabushiki Kaisha Toshiba

Hisao Yoshimura

Takeo Maeda

Fumitomo Matsuoka

Shigeru Morita

Masakazu Kakumu

A method for manufacturing a semiconductor device of the present invention has the step of forming an insulation material on a main surface of a semiconductor substrate. A groove is formed to extend from the surface of the material film to the substrate. The groove is buried with a first insulation film. By use of the first insulation film as an etching mask, the material film is removed, so that a projecting portion projecting to the first insulation film from the main surface can be obtained. A second insulation film is formed on a side surface of the projecting portion in a sloped shape, which is from the top portion of the projecting portion to the main surface.

Method for manufacturing semiconductor device isolation region

A method for manufacturing a semiconductor device of the present invention has the step of forming an insulation material on a main surface of a semiconductor substrate. A groove is formed to extend from the surface of the material film to the substrate. The groove is buried with a first insulation film. By use of the first insulation film as an etching mask, the material film is removed, so that a projecting portion projecting to the first insulation film from the main surface can be obtained. A second insulation film is formed on a side surface or the projecting portion in a slope shape, which is from the top portion of the projecting portion to the main surface.

Method for manufacturing semiconductor device

A semiconductor device has a first P type well region (11) formed on an N type semiconductor substrate (10) and a second N type well region (12) formed so as to enclose the first well region. A third N type well region (13) formed on the semiconductor substrate is enclosed by a fourth P type well region (14). The first well region adjoins and is electrically connected to the fourth well region. Contact regions (15, 16) are formed on the first and third well regions to apply a bias voltage to the PN junction between the first and third well regions. An NMOS FET is formed in the first well region and a PMOS FET is formed in the third well region. The drain currents of the NMOS FET and PMOS FET are controlled by changing the reverse bias voltage applied to the two contact regions (15, 16). The depth of the first well region (11) is such that a depletion layer extending below the NMOS FET gate electrode (50) can be connected to a depletion layer formed at an interface between the first and second well regions. The depth of the third well region is such that a depletion layer extending below the gate electrode (5) of the PMOS FET can be connected to a depletion layer formed at the interface between the third and fourth well regions.

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Poughkeepsie, NY, United States of America

Hisao Yoshimura