Comparison of Neutron, Proton and Gamma Ray Effects in Semiconductor Devices

Interest in proton radiation effects has intensified in recent years. A prime focus is the relationship between proton displacement and ionization effects and the separate consideration of neutron-induced displacement and gamma-ionization effects in TREE characterization. Recent definitive work on proton and neutron displacement damage in silicon in terms of nonionizing energy loss has laid the groundwork for comparison of proton effects with the TREE data base. We initiate this comparison with a summary of device radiation susceptibilities in neutron and gamma environments. Proton interactions in silicon devices are then presented in terms of dose deposition and nonionizing energy loss. This leads to a neutron-proton damage equivalence factor and enables the development of simple correspondence. The device susceptibility charts are then combined so both displacement damage and ionization-damage can be schematically examined relative to proton dose. These susceptibility charts demonstrate the dominance of ionization effects for damage in a proton environment for modern silicon microcircuit technologies. This approach is presented as a convenient means of interpreting effects for both proton exposures and TREE simulators. It is concluded that TREE characterization can be used as a good first-order estimate of proton damage effects.