Evidence for angular effects in proton-induced single-event upsets

Historically, proton-induced single-event effects (SEES) ground test data are collected independent of the orientation of the microelectronic device to the proton beam direction. In this study, we present experimental and simulation evidence that shows an effect of over an order of magnitude on the proton-induced single-event upset (SEU) cross section when the angle of incidence of the proton beam is varied. The magnitude of this effect is shown to depend on the incidence proton energy and the device critical charge. The angular effect is demonstrated for Silicon-On-Sapphire and Silicon-On-Insulator technologies, but would not necessarily be limited to these technologies.