Semiconductor device having n-channel type MOS transistor with gate electrode layer featuring small average polycrystalline silicon grain size

摘要

In a semiconductor device including a semiconductor substrate, and an n-channel type MOS transistor produced in the semiconductor substrate, the n-channel type MOS transistor includes a gate insulating layer formed on the semiconductor substrate and having a thickness of at most 1.6 nm, and a gate electrode layer on the gate insulating layer, and the gate electrode layer is composed of polycrystalline silicon which has an average grain size falling within a range between 10 nm and 150 nm in the vicinity of the gate insulating layer.