GaN switches in pulsed power

Present research in wide band-gap semiconductors is concentrated predominantly in CW applications. While their applicability for pulsed power is recognized, little work has been done in taking advantage of the individual characteristics of the candidate materials. We describe analysis of the relative merits of the key semiconductor technologies - Si, GaAs, SiC, and GaN - as limited in the pulsed power regime. The discussion includes limitations associated with majority carrier operation and thermal transients. We will also discuss a GaN photoconductor with a vertical topology. This is particularly well suited to higher current applications and also is geometrically more applicable for integration to transmission lines without degrading the high blocking field (~2MV/cm) now available. We will also discuss the relation between the blocking voltage and conduction current typical of majority carrier operation and how using optical carrier generation provides the much higher switching power associated with bipolar operation.