Patent ID: 6168996
Filing Date: 2001-01-02
Classification: H01L

Abstract:
A method of fabricating a semiconductor device comprising the steps of: (a) forming a trench in a semiconductor substrate having a first semiconductor region of a first conductivity type, from a major surface of the first semiconductor region in the semiconductor substrate in a depth direction of the first semiconductor region thereby to form divided portions of the first semiconductor region which are separated by the trench; (b) forming a gate insulating film, including a lower layer of a thermal oxide film and an upper layer of a deposition film, over the internal surface of the trench formed in the first semiconductor region; (c) forming a gate electrode over the gate insulating film in the trench; (d) introducing, after said step (c), impurities into the semiconductor substrate to form a second semiconductor region of a second conductivity type in each of the divided portions of the first semiconductor region; and (e) introducing, after said step (c), impurities into the semiconductor substrate to form a third semiconductor region of the first conductivity type in each of the divided portions of the first semiconductor region, whereby the resultant second semiconductor region is formed at a place deeper than the third semiconductor region, and the second semiconductor region is formed between the third semiconductor region and the resultant first semiconductor region in the depth direction.