| 摘要 |
PURPOSE:To prevent the variation of threshold values of a MOS transistor due to irradiation damages, by forming a gate insulation film into a double layer structure of an Si3N4 film and an SiO2 film. CONSTITUTION:In the MOS transistor, the gate structure is formed into the double layer one of the SiO2 film 2 and the Si3N4 film 4. In the Si3N4 film, electrons have the property of being easily captured. Therefore, by forming a double layer structure of films 2 and 4, even when the incidence of radioactive rays into the gate film generates pairs of electrons.holes, holes are easy to be captured in the film 2 and electrons in the film 4, and accordingly an electrically neutral state is kept in the gate film. When an SiO3 film is grown on an Si substrate 1, holes are easy to be captured in the neighborhood of the interface between the Si substrate and the SiO2 film. Therefore, it is advisable to grow an Si3N4 film on an Si substrate. |
