POTENTIAL OF PLASMA GROWN OXIDE FILMS FOR SURFACE PASSIVATION OF CRYSTALLINE SILICON SOLAR CELLS

摘要

We report on the growth of thin silicon oxide films in an inductively coupled plasma chamber at a lowtemperature of 320°C. The films were grown in oxygen (O2), oxygen + argon (O2+Ar), oxygen + nitrogen (O2+N2),and nitrous oxide (N2O) ambients. The film composition is studied using fourier transform infrared spectroscopy(FTIR), and the presence of interstitial oxygen and Si-Si unsaturated bonds was confirmed for films grown in oxygenambient. Optical emission spectroscopy was used to study the atomic oxygen intensity within the plasma for variousambients used in the experiments, and its potential correlation to the amount of interstitial oxygen in silicon. Thefilms were capped with a silicon nitride layer (SiNx:H), and capacitance - voltage measurements were carried out.The minimum mid-gap interface state density was obtained for the stack comprising of the film grown in N2O plasmaambient. The surface recombination vel°City (SRV) was found to be the lowest for the stack based on oxide filmgrown in N2O ambient. The same stack showed lower SRV when compared to films grown in oxygen ambient, afterannealing at 400°C and after firing at 800°C.