The surface gate forma electrostatic induction thyristor null which possesses silicon thin film formation ballast

摘要

PURPOSE: To improve a controllable on-state withstanding current and enlarge a safety working range, by constituting a centralized current control function, in which a first high-density layer is formed selectively with a fine pattern, and a silicon thin-film layer is inserted between a first high-density layer and a cathode electrode. ;CONSTITUTION: A silicon thin-film layer 9' is inserted between a cathode electrode 9 and a first high-density layer 4 provided in a place 3 at one side of a semiconductor 2, and at the same time the first high-density layer 4 is selectively formed with a fine pattern. An insulating layer 7 is formed between the high-density layer 4 and the silicon thin-film layer 9' that is made of polysilicon or amorphous silicon. In this way, current concentration is attenuated and a controllable on-state withstanding current is improved since the current is limited even when an anode current leaks from a unit cell having a higher voltage gain to another unit cell having lower one. Moreover, a safety working range is enlarged and becomes larger than that of the conventional devices.;COPYRIGHT: (C)1993,JPO&Japio