Performance of electron beam-semiconductor amplifiers

Experimental results obtained with developmental electron beam-semiconductor devices used as video-pulse and RF pulsed amplifiers are discussed. These devices employ a grid-modulated electron beam to control the current in a semiconductor target. Power gains of 26 dB and peak pulse powers of 40 W were obtained at up to 600 MHz with an untuned output impedance of 20 Ω. Peak powers in excess of 30 W were obtained at 600 MHz with a 50-Ω load. Power gains of 20 dB were obtained at up to 860 MHz for both output impedances. Also described is the performance of a video-pulse amplifier with a peak power of 2 kW and a rise time of 2 ns. The experimental results are compared to the theoretically predicted values. A problem of diode deterioration encountered with these developmental devices is discussed and solutions to the problem are presented. The reverse breakdown characteristic of both nonpassivated mesa diodes and silicon dioxide passivated planar diodes using "p on n" material decreased by over 50 percent during the first few hours of operation. "p on n" diodes with phosphorous glass over the silicon dioxide have been operated up to 59 h with little deterioration, and a planar diode with "n on p" construction has been operated satisfactorily for 1000 h.