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 and having a first region and a second region adjacent to each other along the upper surface thereof over the substrate; (c) forming a first semiconductor region of a second conductivity type different from the first conductivity type over the upper surface of the semiconductor layer in the first region and forming a second semiconductor region of the first conductivity type over the upper surface of the semiconductor layer in the second region; (d) after the step (c), sequentially forming a first insulating film and a first semiconductor film including a material having a larger oxidation rate than silicon carbide over the semiconductor layer; (e) exposing the upper surface of the first insulating film by opening the first semiconductor film in the first region; (f) exposing the upper surface of the first semiconductor region in the first region by opening the first insulating film exposed from the first semiconductor film by a wet etching method; (g) after the step (f), forming a gate insulating film over the semiconductor layer in the first region by oxidation treatment and forming a second insulating film containing a film formed by oxidizing the first semiconductor film and the first insulating film and having a film thickness larger than the gate insulating film by the oxidation treatment; and (h) embedding and forming a gate electrode between plural parts of the second insulating film opposing to each other with the first region interposed therebetween.