JPS5617039A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the generation of an inversion layer under a film by a thin oxide film in a semiconductor device by forming a conductive substance durable for relatively high temperature in a field oxide film and connecting it to a substrate. CONSTITUTION:An SiO2 thin film 9 is formed on an Si substrate 1, a resist mask is formed thereon, an ion is implanted to form an inversion preventive layer 1' thereon, and an SiO2 film 9 is then perforated. Thereafter, a conductive substance 11 durable for relatively high temperature such as polysilicon or the like is accumulated thereon to diffuse the same conductivity impurity as the substrate 1 therein, and an SiO2 thin film 12 is coated thereon. Subsequently, a resist mask is coated thereon, openings are etched thereat, a gate oxide film 6 is formed on the substrate 1 being exposed, and a polysilicon film 7 is laminated thereon. Then, a resist mask is coated thereon, openings are selectively perforated thereat, and source and drain layers 5 are formed thereon. Since this configuration has equal potential in the film 11 to the substrate even if a voltage higher by double than the power supply voltage is applied to the polysilicon layer 8 for wiring, the inversion layer is formed only on the surface of the film 11 in the boundary between the films 12 and 11, but is not produced on the surface of the substrate.