Sensitivity Prediction Of Single Event Effects Induced By Protons In Semiconductor Devices

Space radiation environments in which satellites and spacecraft are flying contain a large amount of high-energy protons. These protons could induce single event effects in semiconductor devices and severely destroy the operational stability of the device. Therefore, estimating proton single event effect cross-sections and calculating spatial error rates for the spaceflight devices are vital to the safety guarantee of the satellite in orbit. Nowadays, the most commonly used theoretical methods of predicting proton single event effect cross-sections give inaccurate predictions in many circumstances. In order to improve the prediction accuracy and meet the aerospace engineering needs, the following researches are carried out in this thesis.Firstly, established the computer simulation code PRESTAGE to estimate proton single event effect cross-sections. The critical charges varying according to the location in the sensitive volume are calculated mainly from the Weibull fitting of the heavy ion test data. PRESTAGE adopts Monte Carlo package Geant4 to simulate the physical interactions between the incident proton and the device materials, including the electronic ionization, elastic and inelastic collisions of the nucleus, and the nuclear fission. The amount of charge that is generated in the sensitive volume by the primary and secondary ions is compared with the corresponding critical charge, and if the generated charge exceeds, a single event effect is counted. In comparison to semi-empirical methods, PRESTAGE describes the sensitive volume and physical processes in a more complex and comprehensive way and enables more realistic simulations of proton single event effect mechanisms. Calculations for more than 20 devices show that using PRESTAGE for calculations of single event upsets caused by proton indirect ionization leads to higher estimate accuracy. In addition, PRESTAGE can also accurately predict single event latch-up and proton direct ionization effects for which semi-empirical models fail to calculate. Calculative errors of PRESTAGE in most cases are less than 2-3 times.Secondly, the sensitivities of PRESTAGE calculations to variation of input parameters are studied. In examining the impact of a certain input parameter, vary that parameter within a certain range, keep the other parameters unchanged, and observe the variation trends of the PRESTAGE calculated results. The study shows that when calculating the single event upset cross-section induced by proton direct ionization, PRESTAGE calculation results significantly change with changes in the sensitive volume and passivation layer thicknesses. When calculating cross-sections induced by proton indirect ionizations, PRESTAGE is not sensitive to the change of the passivation over layer thickness, and the calculation results stay constant as the thickness of the sensitive volume varies within the range of 0.05～2 μm. In other ranges, the calculated cross-section decreases with the increasing of the sensitive volume thickness. These study results provide important references for the engineering application of PRESTAGE.Finally, PRESTAGE is used to predict the proton single event latch-up error rates of the VATA160 chip. As an example of PRESTAGE using in practical engineering projects, the spatial error rates of the VATA160 chip in the satellite DArk Mater Particle Explore (DAMPE) are estimated. Calculation results show that the averaged spatial error rate for the VATA160 chip is approximately 2×10-5/device/day. Worst-case error rates are 1～3 orders of magnitude higher than the averaged one. Since 32 VATA160 chips are applied in the satellite for a mission of at least 3 years, the number of expected latch-up events on orbit is not negligible. Therefore, effective single event latch-up protection circuits with fast response should be added into the electronics system to avoid catastrophic damages.PRESTAGE uses Geant4 and heavy ion test data to realistically simulate the mechanism of proton single event effects, and thus improves the estimation precisions of the effect cross sections as compared to the semi-empirical methods. The PRESTAGE calculated error rates of the VATA160 chip provide valuable references for the anti-irridiation evaluation in the DAMPE project.