Modeling-Based Design of the Control Pattern for Uniform Macrostep Morphology in Solution Growth of SiC

Abstract

In the solution growth of the SiC crystal, macrosteps with sufficient height on an off-axis substrate are required to reduce defects and achieve a high-quality grown layer. However, overdeveloped macrosteps can induce new defects and adversely affect the crystal quality. To better understand and control the behavior of macrosteps corresponding to the control parameters of the growth system, a simulation method that consists of a global twodimensional computational fluid dynamic (CFD) model, a local three-dimensional CFD model near the growth front, and a kinetics model that describes the movement of macrosteps on the crystal surface is proposed. The simulation method is first applied to investigate the effect of the crystal rotation speed on macrostep morphology. Although the results indicate that a higher crystal rotation speed results in less step bunching, constantly rotating the crystal in one direction is demonstrated to be incapable of yielding a uniform macrostep distribution on the whole surface. Accordingly, a sophisticated control pattern is designed by periodically switching the flow direction underneath the crystal surface, where the proposed simulation method is critical to determine detailed control-parameter values. When the control pattern suggested by the simulation is used, a grown crystal with a uniform macrostep morphology and ideal step height on the whole surface is obtained in the practical experiment.

Effect of Solution Components on Solvent Inclusion in SiC Solution Growth

“…4,5 TSD transformation requires a sufficient height of macrostep. However, higher macrosteps can easily lead to instability of the steps, resulting in inclusions, 6,7,8 which renders SiC unsuitable for device fabrication and evaluation. 9,10 Prior research indicates that the formation of inclusions can be attributed to step morphological instability.…”

Effects of proton implantation for expansion of basal plane dislocations in SiC toward suppression of bipolar degradation: review and perspective

“…Wafers with epitaxial layers have been employed for the mass production of SiC devices and are currently commercially available. Although significant research effort has been devoted to improving wafer quality, [1][2][3][4][5][6][7] wafers currently on the market contain various types of defects. In addition, both the density and distribution of defects vary widely between wafer batches.…”

Suppression of SiC Inclusions in 4H-SiC Crystals Grown from Si–Cr–C-Based Solution Saturated with SiC

“…First, severe step bunching is very likely to occur during solution growth. Step bunching often introduces macrodefects accompanying solvent inclusions. − Although many studies have been dedicated to suppressing step bunching by optimizing the solvent composition ,− or solution flow (mass transport) behavior, ,,− this problem still hinders the use of solution growth to form large-size bulk 4H-SiC crystals.…”