| 摘要 |
A charge retention characteristic of a nonvolatile memory transistor is improved. A first insulating film that functions as a tunnel insulating film, a charge storage layer, and a second insulating film are sandwiched between a semiconductor substrate and a conductive film. The charge storage layer is formed of two silicon nitride films. A silicon nitride film which is a lower layer is formed using NH<SUB>3 </SUB>as a nitrogen source gas by a CVD method and contains a larger number of N-H bonds than the upper layer. A second silicon nitride film which is an upper layer is formed using N<SUB>2 </SUB>as a nitrogen source gas by a CVD method and contains a larger number of Si-H bonds than the lower layer. |
