| 摘要 |
PURPOSE:To prevent the dielectric strength of a drain from declining by a method wherein a stopper diffused layer is pushed in by oxidization in an atmosphere of a low pressure and a required oxide film is formed under a high pressure. CONSTITUTION:An Si3N4 mask 13 is formed on SiO2 12 on a P type Si-substrate and B-ion is implanted to form a P layer 16. While the oxidization is carried out in an atmosphere of 1-4 atm, because the oxide film grows slowly, the channel stopper 16 is diffused more deeply. Then a required field oxide film 18 is formed by oxidation under a high pressure not less than 4 atm. Then an N type MOSFET is formed by a conventional method. With the above configuration, the oxide film can be formed in a short period after the stopper region is pushed in deeply, so that the dielectric strength of a drain does not decline and an FET with a high dielectric strength can be obtained. |
