Evolution of defect complexes in silicon single crystals with heavy fluence 10 MeV proton irradiation

We have investigated the defect structure of 10 MeV proton irradiated Czoch ralski-grown Si single crystals and space solar cells with boron-doped p-Si base layer using deep level transient spectroscopy measurements to charact erize both vacancy interstitials and their complex-type defects and to moni tor their evolution upon annealing at temperatures less than or equal to 50 0 degrees C. We have observed quite different annealing behavior of the dee p levels for conduction-type converted samples (n-type) irradiated at 1 x 1 0(14) p/cm(2) as compared to an intermediate dose of 3 x 10(13) p/cm(2). Th e observed concentrations of the minority carrier level at E-C-0.20 eV and the new electron level at E-C-0.71 eV that can be seen in type converted sa mples, have been found to be enough to account for the carrier removal effe cts. The present study also throws light on the fact that heavy proton irra diation not only changes the structure of the device (from p to n type) but also makes the defect structure complex as compared to the simple defect s tructure in low dose samples. Isochronal thermal annealing after heavy irra diation provides interesting insight into defect interactions. In particula r, the new observed prominent electron level (E-C-0.71 eV) in type converte d cells exhibits a mutual thermal transformation with hole level (E-V+0.36 eV) upon annealing. (C) 2000 American Institute of Physics. [S0021-8979(00) 04804-0].