Fuji Electric Co., Ltd.

Toshihiro Arai

Yasushi Niimura

Takayuki Shimatou

Hideki Shishido

Tatsuhiko Fujihira

Takeyoshi Nishimura

Takashi Kobayashi

To easily assess a feedback capacitance of a semiconductor element. An assessment method of assessing a feedback capacitance of a semiconductor element is provided, the assessment method including:

Assessment method, and semiconductor device manufacturing method

To easily assess a feedback capacitance of a semiconductor element. An assessment method of assessing a feedback capacitance of a semiconductor element is provided, the assessment method including: acquiring a first characteristic correlated with the feedback capacitance and a second characteristic correlated with the feedback capacitance; and assessing the feedback capacitance based on the first characteristic and the second characteristic. The first characteristic may be a characteristic that corresponds to a withstanding voltage of the semiconductor element, and the second characteristic may be an on-resistance of the semiconductor element. In the assessing, the feedback capacitance may be assessed based on a ratio between the first characteristic and the second characteristic.

The invention improves the withstand voltage and avalanche withstand capability of a MOSFET, by preventing avalanche currents from localizing to the corners of the quadrangular cells of a MOSFET. The MOSFET includes a square channel region of the second conductivity type formed in a surface layer of a semiconductor substrate of the first conductivity type, a well region of high impurity concentration formed in the central portion of the channel region, a source region of the first conductivity type formed in a surface layer of the well region, and a MOS structure formed on the surface of the above described constituents. The cell structure, in which a diagonal of the square channel region and a diagonal of the nearest neighboring channel regions lie on a line, narrows a spacing between the corners of the neighboring channel regions to encourage pinch-off of a depletion layer and suppresses localization of avalanche currents to the corners of the channel regions. By connecting the corner of the neighboring channel regions with stripe regions of high resistivity, the depletion layer expands more easily.

Growing community of inventors

Matsumoto, Japan

Toshihiro Arai