The introduction of dislocations during the growth of floating-zone silicon crystals as a result of point defect condensation

Abstract

During growth of dislocation-free floating-zone crystals two types of “swirl defects” (A- and B-clusters) are formed as a result of point defect condensation. The diffusion coefficient of these point defects (vacancies, silicon interstitials) in the temperature interval 1050–1100 °C, is found to be 2 × 10 -5 cm 2/sec. Section topographic analysis showed that the A-clusters (dislocation loops) rapidly increase in size with decreasing crystal cooling rate. This is attributed to a combined climb-glide process. Evidence is presented that the predominant cause for the loss of dislocation-free growth, particularly of large-diameter crystals, is due to emission of dislocation arrays from the A-clusters.