A theoretical model accounting for the experimental results of electron beam induced current (EBIC) collection efficiency on Al-n Si diodes and Si n + p cells, subject to various heat treatments, has been put forward. Twelve samples have been investigated, i.e., monocrystals and polycrystals, oxidised and non-oxidised, and this, at three (03) different temperatures (800°C during 60 mn, 850°C during 12 mn and 900°C during 7 mn). The framework adopted has highlighted the importance of some parameters, such as the minority carrier diffusion length, their superficial recombination velocity, together with a carrier trapping velocity. The mutual influences of the material microstructure under study, the temperature and the treatment time have also been analysed.