Characterization and PL properties of Ge-induced crystallization of a-Si films deposited by magnetron sputtering

In this paper, we present the characterization of Ge-induced crystallization of amorphous Si (a-Si) films deposited by magnetron sputtering. The film structures of a-Si films were characterized by Raman spectroscopy, Atomic Force microscope (AFM), and field emission scanning electron microscope (FESEM). The result show that 60% of a-si film with a layer of 400 nm Ge buried is crystallized at growth temperature of 800 degrees C. The surface roughness and average surface grain size obtained by AFM is 2.39 nm and 60 nm for the crystallized film, respectively. The films growth at temperature of 500 degrees C and 650 degrees C shows a PL spectrum band from 1.6 eV to 1.8 eV, and the PL peak shifts to lower energy as the growth temperature increased. As for the film grown at 800 degrees C, the PL spectrum is nearly extinguished. The crystallization of a-Si film induced by buried Ge might be a useful technology to develop high quality poly-Si film without annealing.