Microscopic study of the H2O vapor treatment of the silicon grain boundaries

We have proposed annealing in H2O vapor as a new effective and low-cost method for passivating polycrystalline silicon grain boundaries and for improving the performance of poly-Si based devices. The effect of H2O vapor treatment was experimentally found to differ from analogous anneal in nitrogen and hydrogen. Mechanism of the H2O vapor treatment was studied by Kelvin force microscopy, used to measure the potential change at individual grain boundaries and point defects. The potential change was dependent on the grain boundary character and it correlated with the crystalline disorder and internal stress observed by microscopic Raman spectroscopy. Effect of H2O vapor passivation was experimentally connected with the potential change at the grain boundaries before and after the treatment.