Au-Catalyst Induced Low Temperature (∼250 ºC) Layer Exchange Crystallization for SiGe On Insulator

The gold-induced crystallization technique has been investigated to achieve poly-SiGe films on insulators at low temperatures (300oC). By annealing of the amorphous SiGe (Ge concentration: 0-100%)/Au stacked structures formed on insulating substrates, positions of the SiGe and Au layers are inverted, and the Au/SiGe stacked structures are obtained. Crystallization of the SiGe layers in the inverted samples is confirmed by the Raman scattering spectroscopy analysis. Moreover, the Raman measurements reveal that the Ge fractions in the crystallized SiGe layers are almost the same as those of the initial amorphous SiGe layers. This gold-induced layer-exchange crystallization technique of SiGe layers at a low temperature (~250oC) will be very useful to obtain poly-SiGe layers on plastic substrates, which are essential to realize flexible high-speed thin-films transistors and high-efficiency solar cells.