Annealing Temperature Dependence of Crystallization Process of SiGeAu Thin Film

The large thermoelectric power of SiGeAu thin film depends on the sizes of microcrystals and the crystalline fraction of thin films. We investigate the crystallization process and control method of the microcrystal size and crystalline fraction. In the samples with 7 and 12 at. % Au, the crystallite diameter of Si 1-x Ge x was constant when the annealing temperature was between 573-773 K and increased with 873 K annealing. These results suggest that there are two crystallization processes depending on annealing temperature: metal-induced crystallization (573-773 K) and liquid phase crystallization (873 K). The crystallite diameter increased with increasing Au composition and crystalline fraction increased with increasing annealing temperature. These new findings provide a strong hint to the control of the sizes of microcrystals and the crystalline fraction of thin films.