Charged particle radiation effects on bulk silicon and SIMOX SOI photodiodes

We report the fabrication of the first n-on-p photodiodes on silicon-on-insulator (SOI) substrates produced using the SIMOX (separation by implantation of oxygen) process. The effects of proton and alpha particle radiation on the optical and electrical performance of these devices have been studied and the results compared to those from bulk Si devices fabricated and tested under identical conditions. In our experiments, the SIMOX SOI photodiodes showed better optical stability and less electrical degradation than their bulk Si counterparts following exposure to charged particles. These results suggest that SOI substrates, in particular SIMOX structures, can potentially be used to fabricate photodetectors and image sensors with improved radiation hardness for space applications.