Anomalous charge collection from silicon-on-insulator structures

An increased single event upset cross-section was found in some silicon-on-insulator (SOI) devices in recent experiments. In order to investigate this unexpected increase we performed both broad beam and microbeam experiments on thermal oxide capacitors. Charge collection was measured using ion beam induced charge collection (IBICC) and time resolved IBICC under different biasing conditions. Lateral charge collection profiles were recorded across the top electrode. We found that the collected charge strongly depends on the applied bias and the oxide thickness. Lateral non-uniformity was observed for low bias conditions. In this paper we will give a qualitative explanation for the charge collection mechanism in SOI devices.