Neutron flux effects in silicon based bipolar junction transistors

Abstract

Irradiation experiments with equivalent neutron fluence and different neutron fluxes were performed to investigate the impact of neutron flux on the radiation damage of silicon based bipolar junction transistors (BJTs). During irradiation the current gain of transistors exposed to higher neutron flux decreased more. However, after annealing of identical time, the current gain of transistors exposed to lower neutron flux displayed greater decrease. These results point out that neutron flux will affect the final damage of BJTs under suitable conditions. Furthermore, a simulation model based on the theory of diffusion-limited reactions was used to analyze the microscopic mechanism. By comparing experimental data with simulative results, a qualitative agreement is obtained and neutron flux effects in BJTs are found to be related to the competition between the formation of stable vacancy associated defects and the recombination of vacancies and interstitials.