JPS5726444A - Manufacture of semiconductor element - Google Patents

Abstract

PURPOSE:To obtain a highly reliable semiconductor element with simple steps by diffusing the entire surface of a substrate, then forming a mesa groove deeper than a P-N junction, again diffusing it to position a P-N junction edge on the bottom of a groove and covering it with a uniform glass layer. CONSTITUTION:A P<++> type layer 21 and an N<++> type layer 22 are accumulated on an N<-> type Si substrate 20, and are covered with an insulating film 23. It is then opened to form a mesa groove 24 reaching an N<-> type layer 20. It is then covered with an insulating thin film 25, is thus driven in, and a P-N junction edge 26 is arrived at the surface of the bottom of the groove 24. The film 25 is chemically etched, and with the residual insulating film on both main surfaces as masks the cross diffused part is etched. Then, a glass layer 27 is covered thereon. The insulating film is removed, and electrodes are attached. According to this method, the P-N junction end is disposed at the surface of the bottom of the groove 24 without selective diffusion step, and since uniformly thick protection glass film can be formed, highly reliable semiconductor element can be obtained.