Process and Contamination Effects on the Single-Event Response of AlSb/InAs HEMTs

We investigate the dependence of the single-event response of AlSb/InAs HEMTs on details of the doping, layer thicknesses, and contamination levels. The transconductance depends on the Δ-doping and layer thickness, which are shown to have the maximum impact on charge collection when the device is biased near the pinch-off voltage. In the on condition (near zero gate bias), the effect is minimal. The possible role of carbon contamination near the substrate-buffer heterointerface in reducing some of the longer transients is discussed.