Influence of RF power on c-Si surface passivation by amorphous a-SiCx:H layers deposited by PECVD

Surface passivation of p-type crystalline silicon (c-Si) wafers has been achieved by depositing phosphorus-doped amorphous silicon carbide films (a-SiC_x:H) in a PECVD reactor. We explored the dependence of effective surface recombination velocity (S_eff) on the RF power supplied to the reactor during film deposition. The effective lifetime (τ_eff) as a function of excess carrier concentration (Δn) was measured by quasi steady state-photoconductance (QSS-PC) technique in order to extract the surface recombination rate. We fitted the experimental τeff(Δn) curve by an insulator/semiconductor model resulting in the determination of the fixed charge density at the interface (Q_f) and the fundamental recombination velocity of holes (S_po). Additional experiments to determine the uniformity of the films along the PECVD reactor plate were carried out.