Tunnel Diode Switching Induced by Transient Ionizing Radiation

Radiation-induced switching in simple bistable tunnel diode circuits at radiation intensities in the range 10810-10 R/s was experimentally investigated at a 17-MeV LINAC source with 40-ns electron pulses. Silicon and gallium arsenide tunnel diodes (0.5-5 mA peak current) were operated at various levels below the peak point voltage and monitored for possible change of state following irradiation. Permissible low-voltage operating points for the bistable circuits where tunneldiodes did not switch to the high-voltage state were determined at several exposure rates. The results of the investigation have applicability in tunnel diode logic and memory array design. Tunnel diodes with higher peak-point currents (5 and 2 mA devices) were found to be more resistant to radiation-induced switching effects. Silicon devices were more consistent in response than gallium arsenide units. Silicon 4.8-mA tunnel diode circuits did not switch when initially biased at 73% peak current at a radiation exposure rate of 1.1 × 109 R/s (44 R).