MODELING AND CHARACTERIZATION OF INTERFACE STATE PARAMETERS AND SURFACE RECOMBINATION VELOCITY AT PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITED SIO2-SI INTERFACE

The effective surface recombination velocity (S(eff)) at plasma enhanc ed chemical vapor deposited (PECVD) SiO2/Si interface as a function of surface band bending under illumination was obtained by combining the photoconductive voltage decay measurements with indium tin oxide gate bias voltage, metal-oxide-semiconductor-capacitance voltage, measurem ents and theoretical calculations. The capture cross sections for elec trons and holes are obtained for the first time for the PECVD SiO2/Si interface state. Theoretical calculations of S(eff) based on the inter face parameters, including interface state density and cross sections for electron and hole, were performed to see the effects of the positi ve oxide charge density (Q(ox)) on S(eff). It is found that roughly a 10 times larger value of Q(ox) compared to the midgap interface state density is required to reduce S(eff) below 10 cm/s for 5 OMEGA cm ( 10 0) p-type Si. These results prove the potential of PECVD SiO2 for effe ctive passivation of Si surfaces for devices like solar cells.