| 摘要 |
The invention relates to crystallization of solid or molten form crystallizable material deposited by a prior art method on a substrate as a layer of thin or thick film. The invention involves subjecting, during heat treatment causing crystallization or recrystallization, the crystallizable material to a standing hypersonic acoustic wave propagating in either bulk or surface mode at a frequency in the range of 1 to 1000 MHz. The standing wave may have a wavelength that is substantially an integral multiple of a crystal lattice parameter of the crystallizable material as, for example, interatomic spacing, and the integral multiple may range between about 10 and 1,000,000. When applied to silicon, a preferred crystallizable material, the integral multiple ranges in a presently preferred embodiment between about 100 and 2,000. To the extent that the resonance conditions for a standing wave on a given substrate and the integral multiple condition cannot both be simultaneously achieved at all times, the resonance requirement is dominant. It is important that the length between peaks of the standing wave be less than or comparable to the crystal size that would be achieved by the same process in the absence of the acoustic wave.
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