| 摘要 |
PURPOSE:To enable to perform effective writing and erasing of a semiconductor memory unit by a method wherein a floating gate layer on the surface of a semiconductor is made to extend over the drain region. CONSTITUTION:The source region 16 and the drain region 17 of N type silicon layers are formed on the P type silicon substrate 11 by ion implantation of N type impurities and thermal diffusion, a gate oxide film 15 is formed by thermal oxidation, and an impurity diffusion layer 12 being the reverse type to the substrate is provided before formation of a floating gate to enlarge the overlapping part between the floating gate layer 13 consisting of polycrystalline silicon and the drain region 17, and to enlarge also junction capacity. A gate layer 14 for control is formed on the floating gate 13 by thermal oxidation, and an insulating film 18 is formed applying the chemical vapor phase growth method. Openings are formed in some parts of the insulating film 18 covering the upper part of the source region 16, the drain region 17 and the gate layer 14 for control, and metal wirings 19, 21, 20 of aluminum are applied respectively on the exposed parts of the openings. Accordingly enhancement of efficiency of erasing action and of writing characteristic can be attained. |
