| 摘要 |
PURPOSE:To manufacture a semiconductor device having multilayer polysilicon layer structure in a short period by implanting the ions of oxygen or nitrogen under conditions, in which a peak is formed at the central section of the film thickness of a polysilicon layer, and shaping double-layer polysilicon layers using the ion implanting section as an insulating layer through heat treatment. CONSTITUTION:A field oxide film 4 and a gate oxide film 30 are formed to a silicon substrate 2, and a phosphorus-doped polysilicon layer 31 is deposited onto these oxide films 4 and 30. Oxygen ions are implanted while using a resist 32 with beltlike openings 34, 36 as a mask to shape oxygen-ion implanting sections 37, 39. The resist 32 is removed, and oxygen ions are implanted so that ions are collected to the intermediate section 42 of the film thickness of the polysilicon layer 31. When an ion implantation region is activated through heat treatment, double-layer polysilicon structure isolated into a first layer polysilicon layer 44 and a second layer polysilicon layer 46 through the oxide film 42 is formed while the first layer polysilicon layer 44 is isolated into oxide films 38 and 40. |
