Effects of post-growth atomic plasma exposure on crystalline grain growth in nanocrystalline silicon

초록

The influence of atomic plasma exposure on the growth of crystalline grains in nanocrystalline silicon (nc-Si:H) was investigated. nc-Si:H films with a low crystalline fraction (similar to 20%) were exposed to either an atomic hydrogen or argon plasma at a substrate temperature of 220 degrees C after deposition. Both plasma treatments were observed to significantly enhance the crystallinity in the films. The crystalline grain growth was shown to be caused by coalescence of subgrains, and the resulting grains are approximately conical in shape. On the other hand, argon exposure was more effective in the growth of grains than hydrogen. A 90-min plasma treatment resulted in an increase of the crystalline phase by factors of 2 and 4 for hydrogen and argon, respectively. We propose that atomic plasma-induced crystallization is mediated by the energy released from energetic plasma atoms.

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