Ionizing Radiation Effects on Indium Antimonide MIS Devices

A study of ionizing radiation effects on InSb MIS devices at cryogenic temperatures has been performed. Measurements of the dependence of flatband voltage shift on total ionizing dose and on applied bias for irradiations performed at 4 and 77° K are presented. Substantial positive charge buildup in the insulating layer causes large flatband shifts, and such shifts potentially constitute a first-order failure mechanism in InSb MIS devices. Holes are trapped in the insulator very near where they are generated, with no transport being evident. A hole trap density of ~8 × 1017 cm-3 is estimated. In pre-irradiation capacitance-vs-time measurements, a strong dependence of storage time on the magnitude of the applied voltage is evident and this effect is attributed to interband tunneling in the InSb depletion region.