Interactions of hydrogen with vanadium in crystalline silicon

In this work, we have investigated interactions of vanadium with hydrogen in n- and p-type float zone grown silicon using deep level transient spectroscopy (DLTS), Laplace DLTS, capacitance-voltage and secondary ion mass spectroscopy measurements (SIMS). Vanadium was introduced into Si wafers by ion implantation with subsequent heat treatments at 800 degrees C for removing the implantation induced lattice damage. In the DLTS spectra of the annealed samples, we have observed two deep level states due to interstitial vanadium (V-i) atoms in n-type Si and one in p-type Si. A comparison of concentration profiles of the V-i atoms with those for the total concentration of V measured by SIMS has shown that at the projected implantation depth the [V-i]/[V-total] ratio is less than 0.05 at chemical concentration of vanadium of 1 x 10(15) cm(-3), so the majority of V atoms are in electrically inactive states in this region. At lower chemical concentrations of vanadium, similar values of [V-i] and [V-total] are observed. After the treatment of the n-type V-doped samples in a remote hydrogen plasma at room temperature, we have found that the concentration of the V-i atoms decreases while additional electron traps emerge in the DLTS spectra. A trap with the highest concentration has been attributed to a vanadium-hydrogen complex. In the p-type Si: V samples, no new levels have emerged in the DLTS spectra after the H-plasma treatments. It is suggested that in p-type Si: V an interaction of H atoms with the V-i atoms is suppressed because of the Coulombic repulsion of positively charged V-i and hydrogen defects. It is argued that no electrically active defects are formed in either the n- or p-type Si: V samples due to possible interactions of hydrogen with electrically inactive V-related defects. We present evidence that annealing of the n-typeSi:V samples in the temperature range 75-125 degrees C following the application of hydrogen plasma results in up to 20% decrease in the total concentration of electrically active V-related defects, indicating the formation of some electrically inactive V-H complexes. Heat treatments at temperatures above 175 degrees C have resulted in the disappearance of all the V-H complexes and recovery of electrical activity of the V-i atoms. (C) 2016 The Authors. Phys. Status Solidi A published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim