A detailed model to improve the radiation-resistance of Si space solar cells

An accurate radiation degradation model, based on measured radiation damage to devices and physical principles on radiation-induced defects in Si, has been established to improve the radiation-resistance of the Czochralski (CZ)-grown and floating-zone (FZ)-grown single-crystal Si space solar cells. We have successfully carried out the optimization of radiation-resistant Si space solar cells by taking into account the effective base carrier concentration dependence of the most important analytical parameters, damage coefficient K/sub L/, for the minority-carrier diffusion length and carrier removal rate R/sub c/ for majority-carriers. The model can be used to adequately predict the radiation degradation of the Si solar cells irradiated with a complete spectrum of electron fluence. It has been established that the radiation-resistance of the silicon solar cell is very dependent on effective carrier concentration in the high fluence range and irradiation tolerance can be improved further by varying the base carrier concentration upon irradiation.