Patent ID: 9269781
Filing Date: 2016-02-23
CPC Classification: H01L

Claim Text:
1. A semiconductor device manufacturing method comprising: forming a second semiconductor region containing silicon carbide of a first conductivity type on a first semiconductor region, the first semiconductor region containing silicon carbide; forming a third semiconductor region containing silicon carbide of a second conductivity type on the second semiconductor region; forming a fourth semiconductor region containing silicon carbide of the first conductivity type on the third semiconductor region; forming a trench in the fourth semiconductor region, the third semiconductor region, and the second semiconductor region; forming an insulating film on a side surface and a bottom surface of the trench; forming a first control electrode portion contacting with the insulating film, the first control electrode portion including a contacting region being in contact with at least the third semiconductor region; adding a material in the contacting region in the trench, the material being such that a dielectric constant of a compound of an oxide or nitride of the material is higher than a dielectric constant of silicon oxide; and forming a high-dielectric constant region in a region of the insulating film that is in contact with at least the third semiconductor region by diffusing the material.