| 摘要 |
PURPOSE:To enhance integration of memory cells by forming a trench at a word line, forming a gate insulating film on the surface of the line, forming a semiconductor layer on the surface of the film, and providing a switching transistor of a vertical direction. CONSTITUTION:A field insulating film 22 is formed by selectively oxidizing the surface of a semiconductor substrate 1, an insulating film 23 for forming the dielectric element of an information storage capacitor on the surface of an active area, a polycrystalline silicon film is then formed by a CVD, then patterned to form a word line 24, and a trench 25 is formed at the line 24 by anisotropically etching. Then, a semiconductor layer 27 made of pure polycrystalline silicon is formed by a CVD, and n-type impurity is ion implanted vertically to form diffused regions 28, 29. Thereafter, a recess is filled with an insulating film 30, a metal film 31 is formed, and the resistance of the line 28 is reduced. Thus, a short channel effect is prevented, and its integration can be simultaneously improved. |
