The use of CVD diamond for high-power switching using electron beam exitation

Depending on purity, diamond could exhibit very high breakdown threshold voltages, high free carrier mobilities and relatively high free carrier lifetimes. For these reasons, diamond has been considered to be well suited for radiation induced high power switching applications in continuous operation mode. Excitation using deep UV sources has been studied but it suffers from their intrinsic low conversion efficiency (below 0.1%). The other problem encountered with deep UV excitation, especially in a bulk configuration, is the short penetration length leading to poor collection efficiencies, polarization and space charge effects. Depending on energy, electron beam excitation should be more adapted for this kind of application. In the present study we report on the conductivity modulation induced by continuous electron beam excitation in CVD diamond samples as a function of electron beam energy and current. The current gain is found to depend strongly on the energy and current of the electron beam. At low electron beam currents continuous gains up to 180 have been measured for 30 keV electrons, believed to be the highest continuous gain ever reported. (C) 2003 Elsevier B.V. All rights reserved.