Oscillating Drop Method Research Articles

Thermophysical property measurements on molten semiconductors using 10-s microgravity in a drop shaft

The effectiveness of 10-s microgravity on thermophysical property measurements on molten materials, such as molten semiconductors, is discussed. The thermal conductivity of molten InSb was successfully measured under microgravity conditions on board the German sounding rocket TEXUS and in a drop shaft in Hokkaido, Japan. Surface tension measurements using an oscillating drop method was attempted in low gravity using a parabolic flight of the NASA KC-135 aircraft. Combined levitation and microgravity, which can provide a contamination-free and undercooled condition. is recommended as a novel approach to obtain missing thermophysical property data on undercooled melts of semiconductors.

電磁浮遊法による高温金属融体の表面張力測定技術

電磁浮遊法による高温金属融体の表面張力測定技術

Surface tension measurement of molten silicon by the oscillating drop method using electromagnetic levitation

The surface tension of molten silicon was successfully measured by an oscillating drop method using electromagnetic levitation over a wide temperature range from 1100 to 1500°C including the undercooling condition of ΔT ≈ 300 K. Single crystals of silicon heavily doped with B and Sb (resistivity as low as 1 × 10 −4 Ω· m ) were successfully melted and levitated. The surface tension of molten silicon was 783.5 × 10 −3 N/m at the melting point of 1410°C within the measurement accuracy of 3–4%; its temperature coefficient was −0.65 × 10 −3 N/m·K. Secondary ion mass spectroscopy (SIMS) analysis showed that O and Sb evaporated during melting, while the B concentration after melting was unchanged. This means that surface tension and its measured temperature dependence correspond to those for a contamination-free silicon melt.