| 摘要 |
PURPOSE:To improve withstanding voltage by providing a process, through which an arsenic doped silicon film is removed through plasma etching, and completely blocking and removing the arsenic doped silicon film. CONSTITUTION:Field oxide films 12, a P-well region 11, an insulating film 13 and gate electrodes 15 having predetermined shapes are formed on a semiconductor substrate 10. A window 16 exposing the surface of the P-well region 11 is bored, and an ADS film 17 is formed on the insulating film 13. A source 18 and a drain 19 for an N type impurity are shaped in the P-well region 11 through heat treatment at a fixed temperature. The ADS film 17 on an element region is changed into an oxide film approximately completely extending over the whole region of thickness thereof through heat treatment. The ADS film 17 turned into the oxide film is removed by using an ammonium fluoride liquid, and removed through plasma etching. The ADS film 17 can be removed completely, and withstanding voltage can be improved. |
