Semiconductor device and manufacturing method thereof
0 Assignments
0 Petitions
Accused Products
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.
20 Citations
18 Claims
-
1-10. -10. (canceled)
-
11. A method of manufacturing a field effect type semiconductor device having a stacked gate insulation film and a gate electrode on a semiconductor layer,
a step of forming said stacked gate insulation film including the steps of forming a thermal oxide film on the semiconductor layer by thermal oxidation, and forming a CVD oxide film on said thermal oxide film by a CVD method so that a ratio of a thickness of said CVD oxide film to that of an entire stacked gate insulation film is at least 20%.
Specification