Permanent deactivation of boron-oxygen recombination centres in silicon

Abstract

The major B–O recombination centres in p-type silicon (labelled SRC) are known to be permanently deactivated at elevated temperature in the presence of excess electrons. This process is accelerated by hydrogen but it occurs also in low-hydrogen material which is the main concern of the present article. A close inspection of the experimental data shows that: (i) the deactivation rate constant Rde is proportional to the electron concentration n and thus completely controlled by the electron lifetime τ and (ii) the value of τ at elevated T is insensitive to SRC; this is controlled by BO2 defects that reconstruct, in the presence of excess electrons, from the initial latent configuration into a recombination-active one (FRC). This scenario accounts for the reported dependence of Rde on temperature, light intensity and the material parameters.