Compositionally Uniform Sige Crystal Growth Aboard The International Space Station (2) Growth Experiments By The Tlz Method And Microgravity Effects

Total of four SiGe crystal growth experiments by the traveling liquidus-zone (TLZ) method have successfully been performed aboard the "Kibo" in 2013 and 2014. Results show that the TLZ method is a powerful method for growing compositionally uniform mixed crystals. On the ground, convection in a melt stops crystal growth and long crystals are difficult to be grown, while in microgravity long and large homogeneous crystals are grown in the diffusion limited regime. Step temperature change by 1 degrees C during crystal growth resulted in interface marking and growth rates in the axial and radial directions were measured precisely. Growth conditions for achieving radial uniformity were obtained. Growth instability at the initial stage was made clear, which was observed in microgravity for the first time. It is shown that convection in a melt has a merit of avoiding such instability.