Hydrogen passivation of iron-related hole traps in silicon

Abstract

We have investigated the passivation of iron-related hole traps in p-type silicon by deep level transient spectroscopy (DLTS) and recombination lifetime measurements. After hydrogen ion implantation (ranging in dose from 1.0×1014 to 1.0×1016 cm−2), all DLTS peaks related to iron impurities disappeared. This indicates that implanted hydrogen passivates the Fe-B pair as well as other iron-related hole traps that are not passivated by hydrogen plasma treatment. On the other hand, two kinds of hole traps were produced at Ev+0.23 eV and Ev+0.38 eV by the hydrogen ion implantation. The recombination lifetime increases from 3 to 18 μs (which is about 45% of the lifetime in uncontaminated samples) with the implantation dose. The maximum value of the recombination lifetime was observed at a dose of 1.0×1015 cm−2. We attribute the decrease in recombination lifetime in more heavily implanted samples (1.0×1016 cm−2) to hole traps created by the ion implantation.