Semiconductor device having a stacked gate insulation film and a gate electrode and manufacturing method thereof
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Abstract
A semiconductor device of the present invention includes an MOSFET which has a stacked gate insulation film formed of at least two types of insulation films, that is, a thermal oxide film provided on a semiconductor substrate and a CVD oxide film provided nearer to a gate electrode than thermal oxide film. The stacked insulation film is provided so that the ratio of the thickness of the CVD oxide film to that of the entire stacked gate insulation film is at least 20%. By such a structure, the gate insulation film thickness is kept uniform. Further, nitrogen may be segregated at an interface between the thermal oxide film and a semiconductor substrate and an interface between the gate electrode and the CVD oxide film. Thus, the occurrence of interface states is prevented between the gate insulation film and the semiconductor substrate as well as between the gate insulation film and the gate electrode. As a result, a semiconductor device with improved gate insulation film and transistor characteristics of an MOSFET as well as a manufacturing method thereof are obtained.
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Citations
21 Claims
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1-18. -18. (canceled)
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19. A field effect type semiconductor device having a gate insulation film and a gate electrode on a surface of a semiconductor layer,
said gate insulation film formed on the surface of said semiconductor layer, said gate insulation film formed by segregating with nitrogen at an interface region between said gate electrode and said semiconductor layer, wherein a concentration of nitrogen along entirety of said gate insulation film, excluding the vicinity of interface region, is higher than the average concentration of nitrogen in said semiconductor layer or said gate electrode.
Specification