MANUFACTURING METHOD OF SEMICONDUCTOR DEVICE AND SEMICONDUCTOR DEVICE

摘要

The present invention makes it possible to improve the accuracy of wet etching and miniaturize a semiconductor device in the case of specifying an active region of a vertical type power MOSFET formed over an SiC substrate by opening an insulating film over the substrate by the wet etching. After a silicon oxide film having a small film thickness and a polysilicon film having a film thickness larger than the silicon oxide film are formed in sequence over an epitaxial layer, the polysilicon film is opened by a dry etching method, successively the silicon oxide film is opened by a wet etching method, and thereby the upper surface of the epitaxial layer in an active region is exposed.

主权项

1. A manufacturing method of a semiconductor device comprising the steps of:
(a) providing a substrate of a first conductivity type containing silicon carbide; (b) forming a semiconductor layer of the first conductivity type containing silicon carbide over the substrate; (c) forming a first semiconductor region and a second semiconductor region of a second conductivity type different from the first conductivity type, and a third semiconductor region of the first conductivity type between the first semiconductor region and the second semiconductor region over an upper surface of the semiconductor layer; (d) forming a fourth semiconductor region of the first conductivity type in the first semiconductor region and a fifth semiconductor region of the first conductivity type in the second semiconductor region; (e) after the step (d), forming a first semiconductor film over the semiconductor layer; (f) forming a patterned first semiconductor film covering the fourth semiconductor region and the fifth semiconductor region and removing the first semiconductor film over the third semiconductor region, a part of the first semiconductor region and a part of the second semiconductor region; (g) after the step (f), forming a gate insulating film over the semiconductor layer by oxidation treatment, and forming a first insulating film by oxidizing the patterned first semiconductor film, over the fourth semiconductor region and the fifth semiconductor region; and (h) forming a gate electrode over the gate insulating film between the first insulating film over the fourth semiconductor region and the first insulating film over the fifth semiconductor region, wherein a thickness of the first insulating film is larger than that of the gate insulating film.