| 摘要 |
PROBLEM TO BE SOLVED: To improve the breakdown voltage and the reliability of silicon oxide film between a polycrystalline silicon layer and a word line on a trench, and to reduce the parasitic capacitance of the word line. SOLUTION: A semiconductor storage device consists of, for example, a p-type silicon substrate 1, a field oxide film 3, a p<+> -type polycrystalline silicon layer 5, a capacity insulation film 5, an n<+> -type polycrystalline silicon 7, a p-type silicon layer 8 and an n<+> -type polycrystalline silicon layer 10, a gate oxide film 12, a cap oxide film 11, a gate electrode 13A, a word line 13B, an n<+> -type source region 14A, and an n<+> -type drain region 14B. The thickness of the cap oxide film 11 ranges from 400 Å to 1,000 Å, which is approximately 1.5 to 4 times larger than 250 Åthat is the thickness of the gate oxide film 12. |
