Modeling of the Growth Rate during Top Seeded Solution Growth of SiC Using Pure Silicon as a Solvent

Abstract

International audienceTo assist the development of high quality single crystalline SiC ingot using the top seeded solution growth process, we have implemented a numerical model with the aim of giving quantitative outcomes in addition to qualitative information. The major role of the convection patterns on the carbon flux is demonstrated. We also evidence that the carbon solubility in liquid silicon is the actual limiting parameter of the SiC solution growth process. A good agreement between computed and experimental growth rates is obtained as a function of temperature, making simulation an adapted predictive tool for the further development of the process

Flow modification enhancing the growth rate in top seeded solution growth of SiC crystals

“…where x C ¼ exp(6.249 -24 460/T) is obtained from the literature. 15,16 The equilibrium condition is supposed to be at the interaction interfaces of melt/graphite and melt/crystal; therefore, a boundary condition C ¼ C 0 was applied on the interfaces of melt/crucible and melt/crystal. A no-ux constraint was applied on the melt surface.…”

Solution Growth of Silicon Carbide Using the Vertical Bridgman Method

“…Due to the fact, that the temperature has a major influence on the growth from solution, experiments with standard parameters but different growth temperatures were carried out. The growth rates of the experiments are compared in Figure .…”

“…Basically all current reports applied top seeded solution growth (TSSG), a modification of the Czochralski process at atmospheric pressures and temperatures below 2000 °C . Due to the strong chemical reactivity of silicon vapour at temperatures above 1800 °C TSSG is carried out below this temperature.…”

Improvement of Growth Interface Stability for 4-Inch Silicon Carbide Crystal Growth in TSSG

“…The crucible is mainly heated by radiation from the furnace. Pure liquid silicon of 11N (Mitsubishi Materials Corporation, Tokyo, Japan) is placed in the internal crucible as a solution [11,12]. The inner diameter of graphite crucible is 100 mm, and it is filled with Si which, depth after melting, is 72 mm.…”

“…ρ Si is the liquid silicon density (kg m −3 ), C eq is the carbon equilibrium concentration (mol m −3 ), x Ceq is the carbon molar fraction, M Si is the molar weight of silicon, M SiC is the molar weight of silicon carbide, ρ SiC is the density of silicon carbide (kg m −3 ), n is the unit vector perpendicular to the crystal surface, and V g is the growth rate. In addition, supersaturation S is defined as deviation from equilibrium concentration in order to show dissolution and crystallization zones [12]:…”