HIGH SPEED POWER AMPLIFIER USING AN ELECTRON SWITCHED P-N JUNCTION

One of the latest design planar silicon dioxide passivated diodes has been fabricated into an EBM tube. The diode used in the tube has a reverse breakdown voltage of 900 volts measured at 300 microamps. The reverse leakage current was 8 microamps at 500 volts. The diode maintained its hard characteristics through sealing the heat sink to the envelope and sealing the electron gun to the glass envelope. However, after processing the diode appeared to be electrically shorted. After a current surge in the reverse direction the diode had a reverse voltage breakdown of 150 volts, and after standing over the weekend this voltage breakdown increased to 300 volts. It is planned to investigate further to try to determine the cause of this apparent deterioration during tube processing. Upon further processing of the gun cathode it was discovered that the heater was opened. The reason for this has not been determined and this tube will be dissected and examined after some further experimenting with the diode. (Author) See also AD-628 858.