| 摘要 |
PURPOSE:To improve a trench capacitor in its capability to reject soft errors attributable to alpha-rays and to place leak currents between neighboring trench capacitors under control by a method wherein arsenic is caused by a high temperature to diffuse out of a coating into the trench inner surfaces through the intermediary of an oxide film for the formation of a high-concentration N-type diffusion layer. CONSTITUTION:A heat treatment process is accomplished at 1000-1050 deg.C in a mixture of nitrogen and oxygen gases for the diffusion of arsenic out of an oxide film 7 into the inner walls and bottoms of a first trench 3 and second trench 4 for the formation of a thin, uniform, high-concentration (approximately 1X10<19>-1X20<20>cm<-3>) N<+> type diffusion layer 9. A thermal oxidation process follows wherein an 100-200Angstrom -thick capacitor oxide film 10 is formed on the entire surface except on a field oxide film 5, which is further followed by vacuum CVD whereby a phosphorus-containing polycrystalline silicon film 11 is formed. |
