| 摘要 |
PURPOSE:To improve the accuracy of a low density drain region width in a semiconductor device by using a polycrystalline silicon gate electrode having a reverse oblique sidewall formed by wafer oblique anisotropic etching as a mask at the time of high density ion implanting. CONSTITUTION:When a polycrystalline silicon film 3 is grown on a silicon dioxide film 2 of a semiconductor substrate 1 and a wafer 1 is inclined to be anisotropically etched in the state that a mask pattern 4 is formed on the film, a gate electrode pattern 3' is formed on sidewalls 6, 7 having anisotropy in a direction 5. Then, low density ions are implanted at 8 from the same direction. Thereafter, a laser light is emitted from an inclined direction 9 to form films 10 on the flat part of the pattern 3' and the sidewall 7, the sidewall 6 is removed by etching by normal anisotropic dry etching, high density ions are then implanted to the whole surface. Then, an ion implanted region 11 is formed. Subsequently, the film 10 is removed by etching, it is heat treated to form a region 12 and a region 13. Thus, an LDD structure that low density drain region width is altered can be obtained with good reproducibility.
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