Energy deposition in gallium arsenide

The single-event-upset phenomena in microelectronic circuits with emphasis on those resulting from nuclear reactions induced by energetic protons is described. The goal is to understand the detailed physical mechanisms leading to SEUs sufficiently to put calculating SEUs on a sound quantitative basis. Previously there was considerable success in predicting the charge generation in well defined slabs of silicon. The purpose of this contract was to try extending the model and the associated simulation codes to GaAs and to begin the experimental measurements necessary to test them. The Clarkson Nuclear Reaction models were modified to handle proton-induced nuclear reactions in gallium arsenide. The codes were immediately useful in analyzing the significance that the edge-effect phenomena, discovered in microbeam studies of GaAs gates, would play in increasing the SEU rates for GaAs memories. Techniques were developed using these codes for calculating SEU rates for select circuits flown in space (9). Two of these circuits, the 2901B and the 93L422 are responsible for SEU problems aboard US satellites. Charge-Collection Measurements have been carriied out using the GaAs Fat-FET test structures from the Rockwell memories.