| 摘要 |
PURPOSE:To obtain a semiconductor device of double structure having small variation of Vth and high mutual conductance gm in simple steps by partly removing the drain side of a gate electrode by anisotropically etching at an angle from obliquely above the drain side, and forming a low density impurity region. CONSTITUTION:After a field oxide film 3 is formed, an antioxidation film or the like is removed, and the entire surface is covered with a gate electrode layer 4 which is made of polycrystalline silicon. After a resist layer 5 is patterned, an ion implantation for forming high density impurity regions 6S, 6D is performed. The gate electrode 4 is etched by anisotropically etching at an angle from obliquely above the drain side. A low density impurity region 7D is formed from the portion etched from obliquely above. The region 7D is formed only at the drain side to achieve a high mutual conductance gm. A double structure of the regions 5D, 6D is formed only at the drain side.
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