A molecular dynamics study of atomic configurations of dislocations accompanying twins in crystal growth of Si from melt
ZY Chang and NG Zhou and C Zhang and HY Gong and MH Lin and L Zhou, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, 26, 085003 (2018).
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 ((1) over bar(1) over bar1) of planes.
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