O. Nast et Aj. Hartmann, Influence of interface and Al structure on layer exchange during aluminum-induced crystallization of amorphous silicon, J APPL PHYS, 88(2), 2000, pp. 716-724
Aluminum-induced crystallization of amorphous silicon (a-Si) is studied usi
ng various microscopy techniques and x-ray photoelectron spectroscopy. Duri
ng the isothermal annealing of subsequently deposited aluminum and a-Si fil
ms on glass, a layer exchange process is induced, while a continuous polycr
ystalline silicon film (poly-Si) on glass is formed within the initial meta
l layer and therefore displaces it. This crystallization process is conduct
ed at temperatures ranging from 350 degrees C to 500 degrees C, significant
ly below the eutectic temperature of the Si-Al binary system of 577 degrees
C. The results presented focus on the influences of the polycrystalline st
ructure of the evaporated Al, the Si-Al layer sequence, and the interface l
ayer between the Al and Si films on the overall crystallization process. Th
ey reveal that the larger the Al grain size of the initial polycrystalline
Al layer, the larger the grain size of the final poly-Si film and the slowe
r the entire layer exchange process. It is further shown that the layer seq
uence, although influencing the speed of the poly-Si formation, has little
impact on the overall layer exchange process. Additionally, evidence is giv
en that an Al oxide interface layer separates the continuous poly-Si layer
from the Al, independent of the original layer sequence. The analyzed oxide
interface layer remains at its position throughout the entire Al and Si la
yer exchange process. An existing phenomenological model of the diffusion-c
ontrolled crystallization during the layer exchange is extended to embrace
the role of the parameters discussed in this paper. (C) 2000 American Insti
tute of Physics. [S0021-8979(00)00514-4].