Effect of annealing on crystalline property of poly-Si thin-film by Ge-induce crystallization

In this paper, an a-Si/Ge thin film with a buried layer of Ge and an a-Si thin film are prepared on Si substrates at a temperature of 500°C by magnetron sputtering. The prepared films are annealed for 5 h at different temperatures in vacuum. The annealed films are characterized by Raman scattering, X-ray diffraction, atomic force microscope and field emission scanning electron microscope. The results reveal that Ge can induce amorphous Si (a-Si) growing at a temperature of 500°C by magnetron sputtering crystallize after annealing at a temperature of 600°C for 5 h. And in the a-Si/Ge thin film the degrees of crystallization of a-Si are 44% and 54% at the annealing temperatures of 600°C and 700°C, respectively. By comparison, a-Si thin film without Ge is crystallized at an annealing temperature of 800°C for 5 h and the degree of crystallization is 46%. The crystallization temperature of a-Si/Ge is reduced by 200°C compared with that of a-Si film without buried Ge layer in the film. The prepared poly-Si thin film possesses high Si(200) orientation with a grain size of 76 nm. The preparation of poly-Si film by Ge-induced crystallization might be a useful technology for developing high-quality poly-Si film.