A molecular dynamics study of atomic configurations of dislocations accompanying twins in crystal growth of Si from melt

Abstract

Based on the Tersoff potential, molecular dynamics simulations for the growth of Si crystals along the 〈112〉 orientation were carried out to investigate the atomic configurations of dislocations and twins. Two typical configurations were observed. One is a sandwich structure which has two twin boundaries and several rows of atoms normally arranged and is ended by a Shockley dislocation with a Burgers vector of 〈112〉/6. The other is composed of two intersecting stacking faults and a Lomer–Cottrell dislocation with a Burgers vector of 〈110〉/6. The two configurations can combine together and form complex atomic configurations in Si crystal. And the two configurations have similar formation processes. Firstly, two twin boundaries or a stacking fault forms in a {111} facet of solid–liquid interface. Then, a dislocation nucleates after the following crystal atom planes dock with each other or the second stacking fault forms. The formation of Shockley dislocation takes a longer time than that of Lomer–Cottrell dislocation due to a larger lattice mismatch () of planes.