Patent ID: 8587085
Filing Date: 2013-11-19
Classification: H01L

Abstract:
1. A semiconductor device, comprising: in a prescribed region of a main surface of a semiconductor substrate, an element isolation part including a trench having a prescribed width, an underlying silicon oxide film embedded in the inside of the trench, a silicon film or a silicon-rich oxide film formed over the top surface of the underlying silicon oxide film, and an overlying silicon oxide film formed over the top surface of the silicon film or the silicon-rich oxide film; and in an active region of the semiconductor substrate surrounded by the element isolation part, a field effect transistor including a gate insulation film including a lamination film of a gate oxide film and a High-k film formed sequentially from the bottom over the main surface of the semiconductor substrate, a gate electrode including a metal film over the top surface of the gate insulation film, a sidewall formed at the side surfaces of the High-k film and the gate electrode, and semiconductor regions formed in the semiconductor substrate on the opposite sides of the gate electrode, wherein the thickness of the overlying silicon oxide film is smaller than the thickness of the silicon film or the silicon-rich oxide film, wherein the thickness of the silicon film or the silicon-rich oxide film is smaller than the thickness of the underlying silicon oxide film, and wherein the ratio of silicon to oxygen in the silicon film or the silicon-rich oxide film is larger than each ratio of silicon to oxygen in the underlying silicon oxide film and the overlying silicon oxide film.