| 摘要 |
PURPOSE:To obtain a thyristor having preferable characteristics by diffusing boron for gettering before forming an oxidized film for selective diffusing, thereby eliminating the defective nucleus generated in the previous step. CONSTITUTION:Aluminum and gallium are diffused from both side surfaces of an N type semiconductor substrate 1 to form a P type region 2 having the prescribed density gradient. Then, borons are diffused from both sides of the substrate 1 to form a high density P type region 5, and the laminated defective nucleus formed at the heat treating time of aluminum or gallium diffusion or before is gettered with boron and eliminated. Thereafter, the both side surfaces are covered by oxidized films 3, but since the generated nucleus does not exist, the oxidization-induced laminated defect is not formed. |
