Metal-induced lateral crystallization (MILC) of amorphous SiGe films on SiO2 has been investigated as a function of Ge fraction (0%–100%) and annealing temperature (320–550°C). High temperature annealing (>500°C) caused spontaneous nucleation in amorphous SiGe with a high Ge fraction (>70%). This suppressed the progress of MILC. Spontaneous nucleation was significantly suppressed by lowering the annealing temperature (<400°C). As a result, large poly-SiGe regions (>20μm) were observed around Ni patterns even for high Ge fractions (>70%). In this way, MILC of amorphous SiGe was achieved for samples with whole Ge fractions (0%–100%).

Position control of solid-phase crystallization in the amorphous Si1−xGex (x: 0–1) films on insulating substrates was investigated by using Ni-imprint technique. Crystal nucleation at the imprinted positions proceeded approximately 2–20 times, depending on Ge fraction, faster than the conventional solid-phase crystallization, which was due to the catalytic effect of Ni. As a result, large SiGe crystal regions (∼2μm) were obtained at controlled positions. On the other hand, the growth velocity did not changed, which suggested that grown regions contained few residual Ni atoms.

No abstract

Electrical and structural properties of polycrystalline silicon germanium (poly-SiGe) films fabricated by pulsed-laser annealing were investigated. Observation of laser-induced melt-regrowth of SiGe films using transient conductance measurement revealed that the melt depth and the crystallization velocity increased as Ge concentration increased. The increase of the crystallization velocity resulted in increase of the average size of crystalline grains from 66 to 120 nm at the laser energy density of 360 mJ/cm2 with increasing Ge concentration from 0 to 60%. The crystalline volume ratio obtained by reflectivity spectra in the ultraviolet region also increased from 0.83 to 1.0. Numerical analysis revealed that the density of electrically active defects decreased from 3.5×1018 to 1.1×1018 cm−3 as Ge concentration increased from 0 to 80%. The density of defect states of Si0.8Ge0.2 films were reduced from 3.5×1018 to 1.9×1018 cm−3 by 13.56-MHz hydrogen plasma treatment at 250 °C, 30 W, and 130 Pa for 30 s. However, the plasma treatment did not reduce the defect density for Si0.4Ge0.6 and Si0.2Ge0.8 films.

Metal-induced low-temperature (≦550 °C) crystallization of amorphous-Si1−xGex (0≦x≦1) on SiO2 has been investigated. In the case of low Ge fraction (0≦x≦0.2), Ge-doping enhanced plane growth was observed. This achieved strain-free poly-Si0.8Ge0.2 with large grains (18 μm). On the other hand, dendrite growth became dominant in the case of intermediate Ge fractions (0.4≦x≦0.6). By optimizing the growth conditions (x: 0.4, annealing: 450 °C, 20 h), very sharp needle-like crystal regions (width: 0.05 μm, length: 10 μm) were obtained. These polycrystalline SiGe films on SiO2 should be used for the system-in-display, three-dimensional ultralarge scale integrated circuits, and novel one-dimensional wires.

Articles you may be interested inNucleation and growth kinetics during metal-induced layer exchange crystallization of Ge thin films at low temperatures J. Appl. Phys. 111, 044908 (2012); 10.1063/1.3682110Self-nucleation free and dimension dependent metal-induced lateral crystallization of amorphous germanium for single crystalline germanium growth on insulating substrate J. Appl. Phys.A model for crystal growth during metal induced lateral crystallization of amorphous silicon Low temperature metal induced crystallization of amorphous silicon using a Ni solution

No abstract

No abstract