Evaluation of Crystal Orientation Dependence of Surface Energy in Silicon

Silicon has been used as semiconductor devices. It is well known that silicon shows a sharp brittle-ductile transition and that silicon is a brittle material at the operative temperature of a device. Hence, it is important to understand fracture behavior to improve the reliability of a device. Because the surface energy, γ_s is considered to affect the fracture behavior of a brittle material, it is important to investigate the crystal orientation dependence of γ_s just after fracture in order to clarify the details of fracture mechanism. This study was carried out to clarify systematically the crystal orientation dependence of γ_s in silicon by molecular dynamics calculation. And it is also carried out to investigate the crystal orientation dependence of γ_s after 1098 K annealing and it was compared with γ_s just after fracture. It is revealed that γ_s of (1̄11) plane has the minimum value. This fact agrees with the experimental fact that cleavage plane of Si is {111}, It is also found that γ_s after 1098 K annealing is lower than that just after fracture. It is concluded that the decrease in γ_s was brought about by the reconstruction of the atoms.