| 摘要 |
PURPOSE:To stabilize the dielectric strength of a planar-structure element with extending a space charge region at a stop voltage applying time to PN junction to make a surface potential gradient low by forming the same conductive-type additional region surrounding the outside of the base region which is provided on a semiconductor substrate. CONSTITUTION:An oxide film is used as a mask to form P-type base region 2 on N-type Si substrate 1, which becomes a collector region, by diffusion, and further, two P-type additional regions 7 and 8 are formed in both sides of region 2 surrounding region 2 by diffusion. Next, N<+>-type region 3 and N<+>-type layer 4 are formed in region 2 and on all the reverse face of substrate 1 respectively by diffusion, and the surface exposed part of the PN junction between regions 2 and 3 is covered with oxide film 10, and the outside circumference surface of it is protected by glass film 9. By this constitution, when the stop voltage is applied to the PN junction between collector region 1 and base region 2, the space charge region is extended and the surface potential gradient is lowered to improve the surface dielectric strength because additional regions 7 and 8 exist. |
