Patent ID: 9716152
Date: 2017-07-25
CPC Classifications: H01L

Claim:
1. A semiconductor device comprising: a semiconductor layer having a trench; a first insulating film formed along an inner surface of the trench; an upper electrode and a lower electrode embedded in the trench via the first insulating film and disposed above and below a second insulating film; and an electric field relaxation portion that relaxes an electric field arising between the upper electrode and the semiconductor layer, the electric field relaxation portion being provided between a side surface of the trench and a lower end portion of the upper electrode, wherein the first insulating film includes a thick film portion contacting the lower electrode and a thin film portion having a thickness less than the thickness of the thick film portion and contacting the upper electrode, and wherein the electric field relaxation portion includes an insulating film provided integral to and between the thick film portion and the thin film portion of the first insulating film and having a thickness greater than the thickness of the thin film portion.