Ge-dependent morphological change in poly-SiGe formed by Ni-mediated crystallization

Low-temperature ( 550 8C) Ni-mediated crystallization of amorphous SiGe (a-Si1 xGex (0 x 1)) layers on SiO2 films has been investigated. The morphology of crystallized SiGe strongly depended on the Ge fraction. For low Ge fractions (<20%), Ge-doping enhanced plane growth was observed, which resulted in strain-free poly-Si0.8Ge0.2 films with large grains (18 mm). On the other hand, dendrite growth was dominant for intermediate Ge fractions (40–60%). Directions and widths of dendrites became straight and narrow with decreasing annealing temperature. Very sharp needle-like crystals (width: 0.05 mm, length: 10 mm) were obtained at the optimized growth conditions (Ge fraction: 40%, annealing: 450 8C, 20 h). These new poly-SiGe films on insulator should be utilized for the advanced system-in-displays and novel devices such as one-dimensional quantum wires. # 2003 Elsevier B.V. All rights reserved