Silicon avalanche cathodes and their characteristics

A highly doped shallow p-n junction (⩽300 Å) is used to fabricate a silicon avalanche cathode (SAC) to serve as an electron source for a micro-vacuum diode. Single and arrayed SACs are integrated on the same chip with separate bias configurations. Since the device fabrication is fully compatible with Si IC processing, high repeatability and reliability are achieved. The device structure and a simple series resistance model are described. An anode collection current of ~0.7 μA is obtained from a single cathode (40-μm diameter), and the emission current is multiplied by the number of cathodes for arrayed cathodes. Emission characteristics are investigated as a function of reverse-bias conditions, anode collection voltages, and cathode diameters. The emission efficiency (anode collection current/total bias current) is found to be almost independent of cathode size; however, higher anode collection voltages increase the emission efficiency