| 摘要 |
PURPOSE:To improve the efficiency of writing by forming a field oxide film on the surface of a substrae while using a double layer consisting of a polycrystal layer and a nitride film as a mask, etching the side of the polycrystal layer and implanting ions from an etched section when forming the EPROM. CONSTITUTION:The polycrystal layer 3 and the nitride film 4 are laminated on the P<-> type Si substrate 1 to which the thin oxide film 2 is shaped, and the surface is patterned by using a photo-resist mask 5. B<+> ions are injected employing the pattern as a mask, and the field oxide film 6 is formed through oxidation. The side of the poly crystal 3 is etched using the nitride film 4 as a mask. B<+> ions are injected into the etched section, and a P<+> region 9 is shaped through heat treatment. When a double gate 13 is formed by employing a normal method, the EPROM is completed. A large amount of hot electrons are generated by the existence of the P<+> region 9, and the efficiency of writing is improved. |
