Electron-beam-controlled high-power semiconductor switches

Theoretical and experimental studies on electron-beam-controlled high-power semiconductor switches are discussed. By using cathodoluminescence as a means to ionize the bulk of the semiconductor switch, it seems to be possible-according to the results of a rate equation model-to control current densities of several hundred amperes per square centimeter with electron-beam current densities in the tens of milliamperes per square centimeter. In experiments on semi-insulating gallium arsenide switches with a zinc-doped cathodoluminescent layer, switch current densities of 53 A/cm² were obtained with an electron-beam current density of 36 mA/cm². The resistance of the switch was lowered by more than four orders of magnitude after the electron-beam was turned on. The closing and opening times were 400 ns, determined by the temporal rise and fall of the thermionically generated electron current. By using laser-generated photoelectrons, closing and opening times in the nanosecond range are achievable