Patent ID: 7595242
Filing Date: 2009-09-29
Classification: H01L

Abstract:
1. A method of manufacturing a semiconductor device having a trench gate type MOSFET, the method comprising the steps of: (a) providing a semiconductor substrate; (b) forming a drain layer over a main surface of the semiconductor substrate; (c) forming a channel layer over the drain layer; (d) forming a first insulating film over the channel layer; (e) removing a part of the channel layer and that of the drain layer while using the first insulating film as a mask to form a plurality of first trenches; (f) after the step (e), forming an epitaxial layer in each of the first trenches and also over the first insulating film; (g) removing a part of the epitaxial layer to expose an upper surface of the first insulating film; (h) after the step (g), removing the first insulating film so that an upper surface of the epitaxial layer becomes higher than that of the channel layer; (i) after the step (h), forming a second insulating film over each of the channel layer and the epitaxial layer; (j) after the step (i), removing a part of the second insulating film to form side wall spacers over side walls of the epitaxial layer; (k) after the step (j), removing a part of the channel layer and that of the drain layer while using the side wall spacers as masks to form a second trench for a gate; (l) removing the side wall spacers and thereafter forming a gate insulating film within the second trench; (m) forming a gate electrode over the gate insulating film; and (n) forming a source region over the channel layer.