Patent ID: 7646072

Claim:
A semiconductor device comprising: a semiconductor substrate; a gate insulating film provided above the semiconductor substrate and containing a metal, oxygen and an additive element; a gate electrode provided above the gate insulating film; and source/drain regions provided in the semiconductor substrate on both sides of the gate electrode, wherein the additive element is at least one element selected from the group consisting of sulfur, selenium, tellurium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten at a concentration of 0.003 atomic % or more but 3 atomic % or less, and wherein the concentration of the additive element is low in a middle part of the gate insulating film but is high in at least one of an area in the vicinity of an interface between the gate insulating film and the gate electrode, and an area in the vicinity of an interface between the gate insulating film and the semiconductor substrate.