Planar, ion-implanted bipolar devices in GaAs

Selected-area ion implantation using heavy metal masks to define the device geometry has been used to fabricate doubly implanted n p n bipolar transistors and planar, isolated p n junction devices in GaAs. The bipolar transistors exhibited common-emitter current gains as high as 25. Collector-base breakdown voltages of 45 V were observed. The junction diodes (∼200 um dia.) exhibited sub-nanoampere leakage currents at 15 V of reverse bias. Surface leakage appears to be the dominant mechanism responsible for the observed leakage currents. The diode forward current is limited by recomination in the space charge region.