Metal induced crystallization of amorphous silicon using layer-by-layer technique with gold ultra thin layer

Abstract

Multilayered films composed of amorphous silicon (a-Si) layer and ultra thin gold layer were prepared for getting polycrystalline silicon (poly-Si) with high crystallization in a short time by metal induced crystallization (MIC) method. Deposition method of the multilayered films was a combination of ion beam evaporation and layer-by-layer technique. We prepared samples with different Au layer thickness of 0.2, 0.4, and 0.8 nm, respectively. The number of a-Si/Au cycle was 50. The samples were annealed at 473, 673, and 873 K for crystallization of a-Si layer. Crystal structure of the films was characterized by X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. Electrical properties were discussed from the resistivity depending on the annealing temperatures. Optical absorbance was measured by UV-visible transmittance spectroscopy. The crystallization of a-Si occurred at low annealing temperature in thicker Au layer films. However, the crystalline volume fraction of a-Si reached to the maximum value when the annealing temperature was 673 K and the Au layer thickness was 0.4 nm. Metallic conductivity was shown in the annealed film of 0.8 nm Au layer thickness. In addition, we found that Au atoms formed nanoparticles in the films by thermal annealing, and a typical peak of surface plasmon by Au nanoparticles observed in the optical absorption spectra.