Transmission behavior of dislocations against Σ3 twin boundaries in Si

Abstract

Transmissions of dislocations across grown-in twin boundaries, i.e., Σ3 {111} boundaries, in multicrystalline silicon (mc-Si) were investigated by direct observations using the etch-pit technique and x-ray topography. Dislocations were freshly generated from a scratch by three-point bending at 800 °C. The generated screw dislocations whose Burgers vector was parallel to the twin boundaries stopped their motion at the boundaries and piled up there. This result reveals that the resistance stress of twin boundaries against screw dislocations is greater than ∼18 MPa. Alternatively, nonscrew-type dislocations were generated from the twin boundaries into the adjacent twinned grain under the stress greater than ∼15 MPa. The results are discussed in terms of cross-slip of dissociated dislocations for transmission across the twin boundaries and stress concentration by piled-up dislocations in the interactions of dislocations with grain boundaries developed in metals.