| 摘要 |
PURPOSE:To make it possible to ignite at a positive low gate bias, by providing locally an n type base layer in such a manner as to pierce a sheetlike p type embedded gate layer having impurity concentration of less than 1X10<18>cm<-3> and leaving it usually in pinch-off position in a depletion layer between gate and base. CONSTITUTION:An n<-> epitaxial base layer 121 is made on a p<+> layer 11, the sheetlike p gate layer 14 whose concentration is less than 1X10<18>cm<-3> is embedded, and an n epitaxial layer 122 is put on it. The layer 122 is etched, an electrode 17 is attached to the gate layer 14, an n<+> layer 13 is provided on the n base 122, an electrode 16 is attached and protected by an insulation film 19. An n<+> layer 111 is selectively formed in such a manner as to pierce the p<+> layer 11, and the p-n junction is shortcircuited by an electrode 15 to shorten ignition time. By making adjustments of thickness and interval of the gate layer 14 and base concentration in the neighborhood of this layer, it is possible to pinch off the channel in absence of the gate bias. When forward voltage is impressed between the positive gate and the cathode 16 and carrier is injected to the channel, the carrier is dispersed in an adjoining SCR structure and an entire aria of the SCR junction is ignited in a moment. It is possible, by using this structure, to obtain the electric field effective type SCR of low ON resistance, high tension resistance and large current. |
