| 摘要 |
PURPOSE:To lessen the surface of a gate in roughness by a method wherein a polycrystalline layer deposited on a gate above the surface of a substrate and a part around it are left as they are when polycrystalline silicon is filled into a trench to form a gate. CONSTITUTION:A polycrystalline silicon 70 is patterned to form a polycrystalline silicon layer 71 on the surface of a substrate, and then impurity 11 is introduced using the layer 71 as a mask. The polycrystalline silicon 71 filled into a groove 9 forms a gate 7. Thereafter, a P<+> layer 4 is formed as a base short resistor through thermal diffusion, an insulating film 8 is made to coat the upside of the layer 71 through the upside of the layer 4, and thus an element can be obtained. By this setup, the surface of a gate is prevented from being roughened, so that the insulating film 8 is improved in covering property. |
