A Deep-Level Transient Spectroscopy Study of Implanted Ge p+n and n+p Junctions by Pt-Induced Crystallization

Abstract

This paper reports on a Deep-Level Transient Spectroscopy (DLTS) study of ion-implanted Ge n+p and p+n junctions, subjected to a 350 oC anneal after Pt-metallization. It is shown that good quality diodes with acceptable reverse current levels can be achieved, pointing to a successful activation and defect removal, especially for the p+n junctions. Nevertheless, DLTS reveals the presence of small concentrations of deep levels, which can be associated with residual ion implantation damage and possibly Pt in-diffusion. In the case of the p+n diodes, the thermal activation energy of the leakage current increases from 0.38 eV to 0.45 eV, which could be in line with the annealing of the deep-level traps, observed in DLTS. The situation is more complex for the n+p junctions, where the low activation energy points to field-assisted leakage current mechanisms, which can be mediated by the residual implantation damage.