PREPARATION OF SEMICONDUCTOR DEVICE

摘要

PURPOSE:To obtain a memory device with high integration and high speed, by stacking on the cut formed on the substrate layers of mainly insulating materials or materials convertible to insulators mixed with impurities and forming a dope region of insulator cover to the wall of the cut. CONSTITUTION:On a P type Si substrate a vertical cut is formed by means of selctive plasma etching and it is filled by an N<+> layer 6, an N<+> layer (bit wire) 1 epitaxially grown. After the surface is flattened, an N<-> charge accumulation layer is epitaxially grown and is covered by twofold masks of an SiO2 7 and resist 10. The N<-> layer 3 is cut vertically by means of plasma etching. After the removal of the mask 10 and coverage of SiO2 7, another plasma etching is performed to remove the film 7 at the bottom and it is covered by SiO2 (polycrystalline Si) 11 with high concentration addition of P type impurities. Again plasma etching is performed to remove the film 11 at the bottom and by heat treatment in N2 a P gate layer 5 is formed by diffusion from the film 11 and it is covered by the SiO2 7. Thereafter metal electrode 2 is mounted to the bottom of the cut and the polyimide resin 9 is applied as a filler and the word wire is mounted to complete the memory device of high integration and high speed.