| 摘要 |
PURPOSE:To improve the characteristics of a groove-type capacitor cell by a method wherein arsenic in first and second coating films containing the arsenic is diffused in a semiconductor substrate and thereby an impurity diffused layer facing a space surrounded by a groove is formed. CONSTITUTION:An oxide film 16a is formed on the bottom part of a groove 13 by coating of a silanol solution of low viscosity containing arsenic of high concentration, and then an oxide film 16b being continuous to the oxide film on the bottom part is formed on the side wall part of the groove 13 by coating of a silanol solution of high viscosity containing the arsenic of high concentration. Accordingly, a continuous shallow N<+> type diffused layer 17 can be formed uniformly and compactly in a region ranging from the bottom part of the groove 13 to the side wall part thereof. In other words, the arsenic in the oxide film 16 is diffused from the inside of the groove 13 into a P-type well 12 through a thin oxide film 20 by heat treatment, and thereby the shallow N<+> type diffused layer 17 of high concentration facing a space surrounded by the groove 13 is formed. According to this method, the impurity diffused layer 17 is formed in continuation, an effective cell capacity is increased and soft error resistance is improved. |
