Studies of high field conduction in diamond for electron beam controlled switching

Experimental studies on a vertical metal‐diamond‐silicon switch structure have been conducted for potential pulsed power applications. Both the dc current‐voltage characteristics and the transient switching response have been measured for a range of voltages. With a 1 μm diamond film, the switch has been seen to withstand electric fields up to 1.8 MV/cm. Our results show a polarity dependence which can be associated with current injection at the asymmetric contacts. Polarity effects were also observed in the presence of e‐beam excitation, and arise due to nonuniform carrier generation near the diamond‐silicon interface. Our switching transients were seen to follow the shape of the e‐beam for a negative bias at the silicon substrate. For positive voltage values exceeding about 80 V however, the switch is seen to go into a persistent‐photocurrent mode. This effect is a result of free carrier trapping within diamond and is enhanced by the double injection process.