PURPOSE: To obtain a highly integrated semiconductor device, which can hardly be subjected to the deterioration of its characteristics in a radiation environment, by using a material including an oxide film, which is grown by using tetraethyl orthosilicate as a gate insulating film of a field effect transistor.

CONSTITUTION: As a gate insulating film 3 of a field effect transistor, a material including an oxide film, which is grown by using tetraehyl orthosilicate. For example, a gate 4 of a polycrystalline silicon film is arranged on a P-type silicon substrate 1 through the oxide film (TEOS film) 3, which is grown by using the tetraethyl orthosilicate. A source 5 of an N+ diffused layer and a drain 6 are provided, and an MIS FET is constituted. In said TEOS film, recombination centers included in the film is many incomparison with a thermal oxide SiO2 film. Therefore, the recombination of electrons and holes generated by incident ionizing radiation is accelerated. The amount of the positive charge captured in traps in the oxide film can be largely reduced. Therefore, the semi conductor device, which has high reliability even in a radiation environment and high integration density, can be obtained.