| 摘要 |
PROBLEM TO BE SOLVED: To reduce cell size while sustaining the layer resistance of buried digit line and ensuring the L margin of channel length of a cell. SOLUTION: The semiconductor device comprises a semiconductor layer (polysilicon film) 3 provided in the active region on the surface of a semiconductor substrate 1 through a gate oxide film 2, a gate electrode (polycide) 12 comprising a conductive layer (tungsten silicide film) 11, a trench 7 made in the gate oxide film 2 to penetrate the semiconductor substrate 1 while being self- aligned, a buried digit line formed of the semiconductor substrate 1 formed in the trench 7 and a diffusion layer 8 of opposite conductivity type, a first insulation film 9 covering at least a part of the surface of the trench and the side face of the semiconductor layer constituting the gate electrode, a second insulation film 10 having high reflow properties filling the trench, and a word line intersecting the trench perpendicularly on the surface of the semiconductor layer and serving as the gate electrode on the active region and as an interconnection layer above the trench. |
