| 摘要 |
PURPOSE:To reduce man-hours and remove the positional displacement of a window, and to obtain desired breakdown characteristics by reutilizing the window for the first selective diffusion for the second selective diffusion. CONSTITUTION:A window 6 is bored to an SiO2 film 5 on a P<-> type Si substrate 4, and P is diffused to form an N<-> layer 2. An SiO2 thin-film 8 as the surface is removed by fluoric acid, B is diffused from the window 6 again, the time for diffusion is adjusted properly, and P-layer 3 is formed in the same shape as the N<-> layer and depth shallower than the N<-> layer. A positional displacement is not generated in the P-layer 3, and it has uniform thickness. Ti 9 is applied, a bump electrode 10 is superposed through Ag plating, and an ohmic electrode 11 is attached on the back of the substrate 4. In the constitution, since the window is bored once, man-hours are decreased, the window is not displaced, the layer 2 having uniform thickness is obtained, and thickness can be controlled accurately by setting the time for diffusion, thus acquiring desired breakdown voltage. |
