THYRISTOR DOTE DE CARACTERISTIQUES AMELIOREES DE TRAITEMENT DU COURANT ET DE LA TENSION

摘要

1301192 Semi-conductor devices GENERAL ELECTRIC CO 27 Feb 1970 [21 March 1969] 9706/70 Heading H1K A thyristor comprises a main current carrying portion surrounding a pilot portion which amplifiers the applied gate signal to "turn on" the main portion of the device via a part of the gate electrode which contacts both the main gate portion and the pilot emitter portion of the device. The pilot portion comprises an annular emitter layer 212 which is connected to the main emitter layer 214 by a bridge portion 216, a pilot gate portion 218 which forms a central part of the main gate portion 220 which main portion is exposed beneath the main emitter layer 214 in the form of radial finger portions 224 each with lateral branches 226, 228, 230 interdigitating with the main emitter layer 214; the further layers 204, 206 being common to both a pilot and main portions of the device. Additionally gate regions 232 symmetrically penetrate the main emitter layer 214 and contact the main cathode contact layer 244. The main gate contact layer 242 contacts the exposed surfaces of the radial finger portions 224 and also the pilot emitter layer 212, through which contact layer the "turn on" of the main portion of the device is initiated. A flat 217 on the annular pilot emitter layer portion 212 ensures that "turn on" is initiated opposite to the bridge portion 216. The pilot gate portion 218 is contacted by the pilot gate contact layer 240. Theperipheral edges of the device may be bevelled to prevent surface breakdown, and increase the applied voltage which may be blocked. In an alternative embodiment the "bridge" portion may not merge with the main emitter portion but terminate short of it, and be of opposite conductivity type to the pilot emitter.