Ion-microbeam probe of high-speed shift registers for SEU Analysis-part II: InP

We report here results of the high speed testing of InP ASICs using Sandia National Laboratories' ion microbeam probe for single event effects. Test results are presented for 4-bit shift registers operating at clock speeds from 0.1 GHz to 10 GHz. We discuss the effects of clock speed and driving voltage on SEU sensitivity, and show that in both cases the increase in vulnerability begins at some threshold rather than being linear over the whole operating range. We also identify and correlate relative SEU hardness to transistor function and show the clock buffers to be the most sensitive part of the circuit. In addition we present a new technique for probing individual transistors that statistically improves the data and use it to show the lateral variations in sensitivity for a discrete transistor.