Neue Emitterkonzepte für Hochspannungsschalter und deren Anwendung in der Leistungselektronik

Abstract

Nowadays conventional power pin-diodes have reached a mature development level in which no essential improvements can be expected. To drastically improve on state and switching properties, new design concepts are needed. Some solutions can be found in the literature. However, they show severe disadvantages from the chip fabrication and applicationpoint of view. New design concepts for silicon diodes with a blocking voltage larger than 2-3kV arepresented in this work. Using an additional gate signal terminal, the emitter efficiency of the p-emitter can be controlled, resulting in a state dependent suitable on-state and turn off bahaviour. The diode is therefore called Emitter Controlled Diode = ECD. Additional advantages are the blocking capability under all operating conditions compared to otherdesign concepts, good turn off characteristics even under critical switching conditions and apositive temperature coefficient. Investigations under severe turn off conditions have shown, that the turn on of a parasitic bipolar transistor is not critical. Comparing the emitter controlled diode with a conventional pin-diode with same power losses the current density can be increased by 30% and the silicon area can be reduced as well. Emitter controlled diodes can be fabricated with the standard power MOSFET production process. No additional masks or local lifetime control is needed.The basic concepts developed in this thesis are used to design an emitter controlled diode.The technological realisation has already been started.