Advances in modeling of wide‐bandgap bulk crystal growth

Abstract

AbstractWe review key aspects of sublimation growth of wide‐bandgap semiconductors like SiC, AlN and GaN, and show how modeling can help to solve a number of practical problems. As the temperature distribution in the growth chamber is the most critical factor in the sublimation technology, we discuss in detail specific features of heat transfer with the focus on the porous materials normally involved in the growth system: powder source, thermal insulation, and graphite. The species transport is simulated using advanced models accounting for a multicomponent vapor and the kinetics of chemical interaction of nitrogen‐containing species with the surface of group‐III nitrides. The effect of growth conditions on parasitic phase formation is analyzed. To optimize the growth system design and operating conditions, we suggest an inverse‐problem approach instead of commonly used trial‐and‐error methods. This simulation procedure has proved quite efficient for getting design solutions, which could hardly be found by conventional straightforward methods. In particular, we demonstrate the effectiveness of the inverse modeling for finding the growth conditions, which provide crystals of desired shapes. A special analysis is made to establish a correlation between the growth conditions and defect distribution in the grown crystal, with the focus on thermoelastic stress produced by temperature gradients. The high‐temperature dynamics of gliding dislocations and consequent plastic stress relaxation in the material is examined. The prospective of global modeling of wide‐bandgap crystal growth by sublimation and still open questions are discussed.