| 摘要 |
PURPOSE:To contrive the improvement in the breakdown withstand voltage of the semiconductor device by implanting ion by utilizing the smooth stepwise difference of an oxide film produced upon selective oxidation of an Si substrate and decreasing the curvature of a P-N junction. CONSTITUTION:An Si3N4 mask 3 is formed on an SiO2 film 2 on an N-type Si substrate 1, is wet oxidized to form a swelled portion 2a. Then, the mask is removed, B ion is implanted to the depth deeper than the film 2 and more shallow than the swelled portion 2a and is uniformly distributed in a direction along the surface to form a P-type layer 5. A P-N junction 6 formed is formed in parallel with rugged surface, and is terminated with low curvature at the swelled film 2a at the end of the film 2. An opening is perforated at the film 2, an electrode 8 is attached therethrough, an electrode 9 is attached onto the back surface of the substrate, is cut at a line 7 to form chips. Since the curvature of the curved surface 10 is smooth according to this configuration to alleviate the electric field concentration end of the P-N junction is protected by the SiO2 film, it can im prove the breakdown withstand voltage of the semiconductor device. |
