Identification of Cr in p-type silicon using the minority carrier lifetime measurement by the surface photovoltage method

Abstract

The effect of CrB pair dissociation on the minority carrier lifetime in p-type silicon is studied using the surface photovoltage (SPV) and deep level transient spectroscopy (DLTS) methods. Experiments were conducted using Cr doped samples (0.5×1012–5×1012 cm−3) with resistivity ranging from 1 to 50 Ω cm. The minority carrier lifetime, increased after the dissociation of CrB by a factor ranging, depending upon resistivity, approximately from 2.0 to 10. This is in contrast to a tenfold reduction observed in the minority carrier lifetime following the dissociation of FeB pairs. The resistivity dependence of the minority carrier lifetime in Cr doped sample can be successfully predicted according to the Shockley–Reed–Hall (SRH) model. It is demonstrated that the defects with energy levels of Ev+0.27 eV and Ec −0.22 eV are the main recombination centers for CrB and Cri, respectively.