Annealing simulations of nano-sized amorphous structures in SiC

Abstract

A two-dimensional model of a nano-sized amorphous layer embedded in a perfect crystal has been developed, and the amorphous-to-crystalline (a–c) transition in 3C-SiC at 2000K has been studied using molecular dynamics methods, with simulation times of up to 88ns. Analysis of the a–c interfaces reveals that the recovery of the bond defects existing at the a–c interfaces plays an important role in recrystallization. During the recrystallization process, a second ordered phase, crystalline 2H-SiC, nucleates and grows, and this phase is stable for long simulation times. The crystallization mechanism is a two-step process that is separated by a longer period of second-phase stability. The kink sites formed at the interfaces between 2H- and 3C-SiC provide a low energy path for 2H-SiC atoms to transfer to 3C-SiC atoms, a process which can be defined as a solid-phase epitaxial transformation (SPET). It is observed that the nano-sized amorphous structure can be fully recrystallized at 2000K in SiC, which is in agreement with experimental observations.