| 摘要 |
PURPOSE:To obtain an electrode or a channel stopper in a substrate, in which decrease in impurity concentration is not found at the upper edge part of a groove, by providing an N<+> or P<+> layer at the side and bottom surfaces of a groove part, with an oxide film or laminated films of the oxide film and poly Si as a mask. CONSTITUTION:A resist mask 3 is provided on a CVD oxide film (a) 2 on a P-type Si substrate 1. A window is provided. With the film (a) 2 as a mask, RIE is performed and a recess groove is formed. By using the mask (a) 2, P ions 4 are implanted to the side surface of the groove obliquely and to the bottom of the groove vertically, and an N<+> layer 5 is formed. The film (a) 2 is removed. The surface is covered with an oxide thin film (b) 6. Poly Si (a) 7 is deposited by a CVD method. Etch-back is performed and the surface is flattened. Only a cell plate part is made to remain. In this constitution, when a cell capacitor having the N<+> layer is formed, the N<+> layer can be uniformly formed on the side surface of the groove, and the decrease in capacitance and the deterioration of bonding with a transistor can be prevented. B ions are implanted and a P<+> layer 11 is provided. An oxide film (e) 12 is embedded. Then, an element isolating region having the P<+> channel stopper 11 is obtained.
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