Doping-Type Dependence of Damage in Silicon Diodes Exposed to X-Ray, Proton, and He $^{+}$ Irradiations

Different amounts of degradation for n-Si and p-Si are observed after X-ray, H⁺, and He⁺ irradiations. Recombination lifetime and forward I-V measurements made on abrupt-junction diodes are compared to theory. Ionizing damage and displacement damage associated with surface and bulk trapping mechanisms, respectively, compete with each other and lead to different behaviors according to the doping type of the silicon on the lightly doped side of the junction. Surface effects are dominant in the n⁺/p diodes compared to the p⁺/n diodes; bulk trapping prevails in the n-Si compared to p-Si. Independently of ion type or fluence, the lifetime damage factor due to irradiation is worse in the p-Si than in the n-Si by a factor of 2-3 times.