Research in Photoconductive Semiconductor Switching (PCSS)

Applied Physical Electronics, LC (APELC) proposes to develop an innovative Silicon Carbide (SiC) Planar Avalanche Switch (PAS) in which a small optical pulse is used to initiate a planar avalanche over a large cross section instead of the filamentary avalanche that is optically initiated in GaAs. The solicitation seeks filamentary avalanche switches based on the large amount of previous work in optically initiated avalanche streamers in GaAs. Non-linear or Avalanche GaAs switches can close with 100s of ps and closure is initiated with only tens of nanojoules of optical energy. However, the GaAs switches are limited to about 20 Amps / filament. Each filament requires additional tens of nanojoules and an elaborate optical system to channel multiple avalanche streamers between electrodes. This designing a switch to conduct several kilo amps is a formidable, if not impossible task. The innovative and PROPRIETARY APELC method of optically triggering a planar avalanche is a revolutionary innovation that is much easier to implement than the overvoltage triggering used to initiate the planar avalanche closure demonstrated in TRAPATT diodes and the Russian Fast Ionization Dynistor (FID) switch. The innovative method used to initiate the planar avalanche requires tens of nanojoules to initiate a planar avalanche per square cm of conduction area and the SiC can handle up to 4 kA per square cm. In addition, the SiC PAS switch, like the avalanche GaAs switch closes in tens to hundreds of ps, the avalanche front traveling at an effective velocity two orders of magnitude greater than the saturated drift velocity in SiC.