The theory and application of bipolar transistors as displacement damage sensors

Abstract

An important aspect of engineering systems for use in extreme environments is understanding the performance of electronic components in radiation environments (e.g., space environments, nuclear reactors, particle accelerators). To accomplish this, experimental and computational modeling approaches are used to understand physical mechanisms that lead to system level failures. When experimentally investigating displacement damage, a common radiation effect, the most important parameter to measure is the particle fluence. An approach that offers benefits over traditional measurement techniques uses the degradation of current gain in silicon bipolar junction transistors as a direct metric for displacement damage in silicon. This thesis covers the bipolar device physics and particle/crystal interactions necessary to understand how displacement damage leads to gain degradation and describes how bipolar devices can be applied as displacement damage sensors to measure particle fluence. The use of bipolar junction transistors as displacement damage sensors in neutron irradiations is demonstrated at lower fluences than previously achieved and first-of-a-kind displacement damage sensor measurements for proton irradiations are provided. The non-ionizing energy loss (NIEL) of each particle is shown to adequately correlate the two particle types, neutrons and protons, across five orders of magnitude of particle fluence using three bipolar junction transistors (2N1486, 2N2484, 2N2222).