| 摘要 |
PURPOSE:To obtain a semiconductor device which is damaged little in a thermal process, whose breakdown strength is high and whose ON-voltage is low by a method wherein a thick silicon substrate is used as the starting material. CONSTITUTION:Two thick n-type silicon substrates 1, 2 are prepared, and a mask which is composed of a silicon oxide film is formed by photolithography or etching. A p-type diffused layer as an isolation layer 5 is formed to be a ring shape. Then, p-type impurities are diffused to the whole surface of every substrate, and a base layer 6 is formed. In addition, n-type impurities are diffused, and an n-type gate-base layer 8, an n-type cathode-emitter layer 9 and an n-type anode-emitter layer 10 are formed. After that, the substrates 1, 2 are polished from the rear side, every p-type diffused layer 5 is exposed on a mirror-polished face, gold is diffused to the polished face, a fault layer 11 is introduced, and a mirror-polishing operation is conducted. Then, mirror- polished faces on the substrates 1, 2 are brought into contact, a heat treatment is conducted, both substrates are bonded directly, and a substrate 12 is obtained. Thereby, it is possible to obtain a semiconductor device which is damaged little in a thermal process, whose breakdown strength is high and whose ON- voltage is low. |
