Relationship between Macrostep Height and Surface Velocity for a Reaction-Limited Crystal Growth Process

Noriko Akutsu

doi:10.1021/acs.cgd.9b00168

Abstract

This work examined the effect of macrostep height on the growth velocity of a vicinal surface during reaction- (interface-) limited crystal growth under non-equilibrium steady state conditions. The Monte Carlo method was employed, based on a restricted solid-on-solid (RSOS) model with point-contact-type step-step attraction (termed the p-RSOS model). Although this is a simple lattice model, the model surface shows a variety of distinctive configurations depending on the temperature and the driving force for crystal growth. The results demonstrate that the surface velocity decreases as the height of the faceted macrostep increases. In addition, the significant variation in surface velocity recently reported by Onuma {\it et al.} in a study based on 4H-SiC was reproduced. This work also shows that the terrace slope, elementary step velocity and elementary step kinetic coefficient are all affected by the faceted macrostep height.

Highlights

The synthesis of high-quality SiC crystals is an important prerequisite for the production of advanced power devices with low power consumption rates
Self-organized faceted macrosteps are known to lower the quality of crystalline SiC,[1] dislocations penetrating the crystal have been shown to end at the side surfaces of macrosteps.[2−4] the intentional introduction of macrosteps can effectively decrease the dislocation density in a SiC crystal
This involved simulating the vicinal surface based on the p-restricted solid-on-solid (RSOS) model and using the Monte Carlo method in conjunction with a system not requiring the conservation of mass

Summary

■ INTRODUCTION

The synthesis of high-quality SiC crystals is an important prerequisite for the production of advanced power devices with low power consumption rates. The aim of this work was to demonstrate the effect of the macrostep height on the surface velocity, the terrace slope, the elementary step velocity, and the elementary step kinetic coefficient in the case of reaction (interface)-limited crystal growth in the nonequilibrium steady state This involved simulating the vicinal surface based on the p-RSOS model and using the Monte Carlo method in conjunction with a system not requiring the conservation of mass. It should be noted that the external parameters included the microscopic ledge energy ε, microscopic step−step attraction εint (

■ RESULTS AND DISCUSSION

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES