Semiconductor device with vertical gate and method of manufacturing the same

摘要

A gate electrode is formed in a trench reaching a drain region so as to leave a concave portion on the top of the trench. A first insulating film is formed, which fills the concave portion and of which the thickness increases as the distance from an end of the trench increases on the substrate surface on both sides of the trench. First and second source regions are formed in a self-alignment manner by introduction of impurities through the first insulating film.

主权项

1. A method of manufacturing a semiconductor device with vertical gate, comprising the steps of:
(a) forming a drain region of a first conductivity type on a semiconductor substrate; (b) forming a first body region of a second conductivity type, which is opposite to the first conductivity type, on the drain region; (c) forming a trench and an adjacent trench adjacent to the trench, each penetrating the first body region and reaching the drain region; (d) forming a gate insulating film on a side wall of the trench; (e) forming a gate electrode in the trench so as to leave a concave portion on the top of the trench after the step of (d); (f) forming a first insulating film that is formed in the concave portion and on a portion between the trench and the adjacent trench, wherein a thickness of the first insulating film formed on the portion increases with an increase in distance from an end of the trench in the first body region to a substantially middle position between the trench and the adjacent trench after the step of (e); and (g) forming a first source region of the first conductivity type, which is disposed along the trench and which is adjacent to the trench, by introduction of impurities through the first insulating film after the step of (f).