| 摘要 |
PURPOSE:To execute densifying, through which film quality is improved sufficiently, without increasing the number of man-hours by forming an oxide film on the surface of a substrate, into which an impurity is introduced, through a CVD method and diffusing the impurity up to predetermined depth through treatment at a high temperature while densifying the oxide film. CONSTITUTION:A thermal oxide film 21 is formed on the N conduction type silicon substrate 1, a window 22 for a P well is bored through photolithography technique, boron is implanted to a surface layer 23 only by 2X10<13>cm<2-2> through an ion implantation method, and the oxide film 24 is deposited only by 0.22mum through the CVD method. When the whole is treated for 9hr at a high temperature of 1,150 deg.C, said implanted boron diffuses up to the depth of 5mum to form the P well while the oxide film 24 is densified and reduced up to the thickness of approximately 0.20mm. The oxide film 24 is brought to the same extent as the thermal oxide film in film quality because it is exposed for a prolonged time at a high temperature, and minute window boring processing for a source region 41 and a drain region 42 can be executed by using a P-etchant. Accordingly, the oxide film coated need not densify independently, and a high-temperature atmosphere can be used, thus largely improving film quality. |
