| 摘要 |
PURPOSE:To contrive to improve a reverse block voltage of a gate cathode by a method wherein a mesa groove is formed by including a p-n surface junction between an n-layer surface and a p-layer on the surface, and the inner wall is covered with a polyimide resin. CONSTITUTION:After selectively providing an n<+> layer 3 by diffusing phosphorus into one surface of an n<-> type Si substrate 1, a p-base 4 and a p-emitter 5 are diffused into both surfaces by Ga diffusion. With an oxide film as a mask, an n emitter 6, mesa grooves 7 deeper than the p-n junction, and the mesa grooves including the p-n surface junction between the layers 4 and 6 are formed. Next, a glass film 8 is formed on the inner wall of the groove 7, and the mesa groove is formed much thicker than the oxide film 9 by means of the polyimide resin. Thereafter, a GTOSCR is completed by attaching electrodes 10-12 by a normal method. By this constitution, the short-circuit accident of the reverse block voltage decreases, since a surface newly exposed by etching the p-n junction between the gate and the cathode is protected with an insulation film; accordingly the instability of charactetistics due to the contamination of the oxide film is eliminated. Besides, the use of the polyimide resin facilitates re- coating. |
