Papers by Keyword: Dislocation Velocity

Abstract: Direct observation of thermal gradient induced motion of basal plane dislocations by in-situ synchrotron X-ray topography imaging of PVT-grown 4H-SiC wafers subject to high temperature treatment has provided an opportunity to analyze the movement of dislocations. Dislocations with Burgers vector along the off-cut [11-20] direction were found to be the only dislocations involved in deformation during heat treatment and the segments of dislocations used for velocity measurements were found to be either pure screw comprised of both Si-and C-core partials or 60° dislocations comprised of purely Si cores. Using the kink-diffusion model, the activation energies for dislocation motion have been calculated from the velocity data for each of these dislocation types and found to be 3.28eV for pure screw and 2.21eV for 60° dislocation segments, respectively.

Abstract: Deformation Characteristics in High-Purity Si Crystals Subjected to Bending Tests Were Studied. Specimens Were Deformed at the Temperatures Higher than 800°C without Brittle Fracture under Application of a High Stress up to 350 Mpa. Stress-Strain Behavior and the Yield Stresses Depend on the Temperature and the Strain Rate. The Results Were Discussed in Terms of the Dislocation Dynamics and Dislocation Mobility to Provide Fundamental Knowledge for Wafer Manufacturing.

Abstract: 4H-SiC samples were bent in compression mode at temperature ranging from 400°C to 700°C. The introduced-defects were identified by Weak Beam (WB) and High Resolution Transmission Electron Microscopy (HRTEM) techniques. They consist of double stacking faults bound by 30° Si(g) partial dislocations whose glide locally transforms the material in its cubic phase. The velocity of partial dislocations was measured after chemical etching of the sample surface. The formation and the expansion of the double stacking faults are discussed.