| 摘要 |
PURPOSE:To prevent erroneous operation due to injected electrons, by surrounding one region of a memory cell array or a substrate-potential generating circuit with a groove having an opposite conductivity type region, and fixing the opposite conductivity type region at a constant potential. CONSTITUTION:On the surface of a P-type semiconductor substrate 1, an insulating film 9 is formed. Thereafter, photoresist 10 is applied. A hole is provided by using a photoetching method. After the insulating film 9 at the hole part is removed, a groove 2 is formed in the substrate 1 and the photoresist 10 is removed. Polycrystalline silicon 11 is grown so as to bury the groove 2. Heat treatment is performed, and an opposite conductivity type region 4 is formed on the surface of the groove 2. Then, the entire surface is etched, and the substrate 1 is exposed. A memory cell array is formed in the inside of the groove 2 through a diffusion process. A substrate-potential generating circuit is provided at the outside. When the opposite conductivity type region 4 is connected to a constant potential, electrons injected from the substrate-potential generating circuit are moved 13 to the memory cell array. Even if the electron came to the array, the electrons are shielded at this part. Thus erroneous operation can be prevented. |
