Gate Bias Dependence of Single Event Charge Collection in AlSb/InAs HEMTs

Single event charge collection in AlSb/InAs HEMTs is shown to depend on the gate bias. Spatial correlation between excess channel carriers and the horizontal field is shown to be the key factor. Hole accumulation in the AlSb buffer layer increases the electron concentration in the two-dimensional electron gas, increasing the collected charge. Potential drop across access regions reduces charge collection towards zero gate bias. A secondary but perceptible dependence on high field electron mobility is demonstrated.