Crystal Growth of Ternary Alloy Semiconductor and Preliminary Study for Microgravity Experiment at the International Space Station

Abstract

Crystal growth of alloy semiconductor has been under investigation at the International Space Station (ISS) to investigate growth kinetics at the solid-liquid interface, because microgravity can suppress the natural convection. In this study, we focused on InGaSb which is one of the promising ternary alloy semiconductors. As a preliminary experiment, wetting angle between the InGaSb and the materials of the ampoule and cartridge, such as quartz, carbon sheet, BN, and C-103 alloy, were measured to check their affinity of the configuration. The InGaSb exhibited much higher wetting ability on the C-103 substrate than that on the other substrates (quartz, BN, and graphite), and this result suggested C-103 can prevent leakage of the InGaSb samples in case the ampoule collapses in the cartridge. On the other hand, BN and graphite exhibited low wetting abilities with InGaSb; therefore, they are suitable materials for the ampoule because they do not significantly affect the InGaSb crystal growth. In another preliminary experiment, concentration of Te dopant, which was added to make striation in the grown crystal, was measured using inductively coupled plasma mass spectrometry (ICP-MS). It is confirmed that Te concentrations were relatively higher at the striation area.

Investigation of directionally solidified InGaSb ternary alloys from Ga and Sb faces of GaSb(111) under prolonged microgravity at the International Space Station

“…Before ampoule preparation, a wettability test of GaSb, InSb, and In x Ga 1 − x Sb materials was performed with the ampoule packing materials, BN, carbon sheet, quartz, and C-103 alloy (cartridge material) at higher temperatures to check the compatibility of these materials during the growth process. 27 The crystals were packed according to the ampoule design, under nitrogen flowing conditions, to maintain an inert atmosphere inside the ampoule, which was evacuated up to 10 − 4 Pa using a turbo molecular pump. The evacuation process was continued for 24 h, and the ampoule was sealed off at this state.…”