Promising Approach for Rapid Growth of High-Quality SiC Crystals Using Si–Nd–C Solutions

Abstract

The solution growth method is a promising technology for growing high-quality silicon carbide (SiC) crystals. However, enhancing C solubility in the growth solution is a key issue in the rapid growth of SiC crystals. In this study, Nd was added to a Si–C solution to enhance the solubility of C and rapidly grow high-quality SiC crystals at low temperatures (1823–1923 K). First, high-temperature chemical equilibrium was used to investigate the temperature dependence of the C solubility in a Si–Nd–C solution. The solubility of C in the Si–Nd–C melt was the highest, compared to those of the conventional Si–Cr–C, Si–Fe–C, and Si–Ti–C melts at the same temperature. The initial Si–Nd alloys used for the solution growth of SiC crystals were determined as Si-(25–42 mol %) Nd at 1823 and 1923 K. Thereafter, a temperature difference method was used to grow SiC crystals from Si-35 mol % Nd, Si-35 mol % Cr, Si-35 mol % Ti, and Si-35 mol % Fe solutions at 1923 K with a temperature difference of 36 K. The solutions producing the largest quantity and size of precipitated SiC crystals in the descending order were Si-35 mol % Nd solution > Si-35 mol % Cr solution > Si-35 mol % Fe solution > Si-35 mol % Ti solution (no SiC crystals). After analyzing and comparing the values for the supersaturation (ΔC) and degree of supersaturation (σ), Si–Nd–C solutions show great promise for use in the rapid growth of high-quality SiC crystals at low temperatures.