Method of fabricating semiconductor device

Abstract

In a method of fabricating a semiconductor device having a MISFET of trench gate structure, a trench is formed from a major surface of a semiconductor layer of first conductivity type which serves as a drain region, in a depth direction of the semiconductor layer, a gate insulating film including a thermal oxide film and a deposited film is formed over the internal surface of the trench, and after a gate electrode has been formed in the trench, impurities are introduced into the semiconductor substrate of first conductivity type to form a semiconductor region of second conductivity type which serves as a channel forming region, and impurities are introduced into the semiconductor region of second conductivity type to form the semiconductor region of first conductivity type which serves as a source region.

1 . 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 semiconductor substrate in a depth direction thereof;    (b) forming a gate insulating film including a thermal oxide film and a deposition film over the internal surface of the trench;    (c) forming a gate electrode over the gate insulating film in the trench; and    (d) introducing, after said step (c), impurities into the semiconductor substrate to form a second semiconductor region of a second conductivity type; and    (e) introducing, after said step (c), impurities into the semiconductor substrate to form a third semiconductor region of the first conductivity type;    the third semiconductor region being formed at a place deeper than the first semiconductor region;    the second semiconductor region being formed between the third semiconductor region and the first semiconductor region in the depth direction.    
     
     
         2 - 21 . (canceled)