Growth of InSb from Moderately Pure Source Elements by Directional Solidification for Improved Economic Viability

Abstract

The purity and structural quality of semiconductor crystals are fundamental to their electronic and optoelectronic performance, making crystal quality a decisive factor in device efficiency. However, achieving such high-quality semiconductors requires high-purity (>= 4N) source materials, which significantly raises production costs. To address this challenge, the present study investigates a cost-effective alternative by growing indium antimonide (InSb) crystals from moderately pure (2N) indium and antimony elements through directional solidification method. As the moderately pure source elements contain various impurities, their incorporation, redistribution during crystal growth, and the properties of the resulting crystal properties were systematically investigated. X-ray diffraction (XRD) and Rietveld refinement confirmed that the InSb crystals exhibited a cubic zinc-blende structure (space group F-43m), with a lattice parameter of 6.4819 & Aring; and a unit-cell volume of 272.338 & Aring;3, reflecting high crystallinity and phase purity. Compositional analyses performed using SEM-EDX and atomic absorption spectroscopy (AAS) revealed a reduction in impurities, with total levels decreasing from 43.54 at % in the starting materials to 24.29 at % in the grown InSb crystal. Transition metals such as Fe, Cu, Zn, Mn, Co, and Ni were effectively suppressed, whereas Al, Bi, and Pb were partially or strongly incorporated into the grown crystal owing to their higher segregation coefficients. Hall-effect measurements indicated p-type conductivity, with a carrier concentration of 3.47 & times; 1019 cm-3 and a resistivity of 5.298 & times; 10-4 Omega cm, thereby demonstrating the good electrical properties of the grown crystal. These findings demonstrate that directional solidification effectively reduces impurity levels and enables the growth of InSb crystals from low-grade source materials, thereby offering a scalable, cost-efficient alternative to conventional purification technique such as zone refining for semiconductor applications.