DETERMINATION OF ENERGY-LEVELS OF RECOMBINATION CENTERS IN LOW-DOPED SI LAYERS BY TEMPERATURE-DEPENDENCE OF RECOMBINATION LIFETIME

The recombination lifetime dependence on temperature and injection lev el is largely due to the actual position of the recombination centers in the bandgap. However in the literature few data have been presented concerning the energy levels of the recombination centers in ''good'' low-doped silicon. In this paper an experimental evaluation of the en ergy position and the spatial distribution of the different recombinat ion centers in low-doped N-type Si samples is made, from the temperatu re dependence of lifetime, by using a differential measurement techniq ue. Results show that the energy levels of the most relevant recombina tion centers detected in such samples are far from being ''deep'', but rather quite ''shallow'', explaining the large variation on lifetime with temperature and injection found experimentally.