Significant improvement in silicon chemical vapor deposition epitaxy above the surface dehydrogenation temperature

We observe an order of magnitude increase in both the rate and achievable thickness of epitaxy by hot-wire chemical vapor deposition at temperatures above the dehydrogenation temperature of the silicon surface. We deposit silicon films on (100) silicon at 110nm∕min at substrate temperatures between 520 and 645°C. At the glass compatible temperature of 610°C, we observe phase-pure epitaxial growth of more than 10μm, as observed by x-ray diffraction and transmission electron microscopy, in contrast to the mixed-phase breakdown seen at lower temperatures. In 610°C films thicker than 4μm, a stable (100)-epitaxial growth mode produces regular surface pyramids with vicinal ⟨311⟩ facets. On the low-energy (111) face of Si, more than 2μm of epitaxial Si were grown at 645°C, but some twinning is observed. The temperature of this new growth regime suggests that rapid dehydrogenation of the growing surface is critical for silicon epitaxy by CVD.

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