SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

摘要

A semiconductor device including a drain region of a first conductivity type formed on a semiconductor substrate; an element forming region that is provided on the drain region and that has a concave portion reaching the drain region; a gate electrode disposed in the concave portion; a superjunction structure portion that is disposed in the element forming region and that is formed by alternately arranging a drift layer of the first conductivity type penetrated by the concave portion and a resurf layer of a second conductivity type being in contact with the drift layer on the semiconductor substrate; and a base region of the second conductivity type that is disposed on the superjunction structure portion so as to be in contact with the drift layer in the element forming region, that is penetrated by the concave portion, and that faces the gate electrode with the gate insulating film therebetween.

主权项

1. A method of manufacturing a semiconductor device having a drift layer of a first conductivity type on a semiconductor substrate of the first conductivity type, the method comprising the steps of:
forming a semiconductor layer of a second conductivity type different from the first conductivity type on the semiconductor substrate; forming a concave portion that penetrates through the semiconductor layer and reaches the semiconductor substrate; forming the drift layer along an inner wall surface of the concave portion by introducing impurities of the first conductivity type onto the semiconductor layer exposed to the inner wall surface of the concave portion; forming an insulating film on the inner wall surface of the concave portion; filling an electrically conductive filler into a bottom part region of the concave portion after the insulating film is formed; removing the insulating film while allowing the filler to serve as a mask; forming a gate insulating film thinner than the insulating film on an exposed surface of the inner wall surface of the concave portion exposed by the removing step, and simultaneously forming an inter-conductor insulating film on an exposed surface of the filler; forming a gate electrode that faces the inner wall surface of the concave portion and the filler with the gate insulating film and the inter-conductor insulating film respectively interposed therebetween; forming a base region of the second conductivity type having an exposed part exposed to the inner wall surface of the concave portion on a surface part of the semiconductor layer by introducing impurities of the second conductivity type from a surface of the semiconductor layer; forming a first conductivity type region exposed to the inner wall surface of the concave portion by introducing impurities of the first conductivity type onto a surface part of the base region at an edge of the concave portion; wherein the filler is filled into the bottom part region of the concave portion that has a predetermined depth which is deeper than the exposed part of the base region in the concave portion, and the base region is formed so that the exposed part of the base region faces to the gate electrode with the gate insulating film interposed therebetween.