Abstract: 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.