Global transient heat transfer simulations are combined with transient point-defect simulations to study the influence of pull-rate variations on the defect distribution in CZ silicon crystal growth. A strong influence of pull-rate variations on the melt/crystal interface is observed. Quasi-stationary and transient results for the interface deflection are compared with experimental data. Furthermore the final point-defect distribution is compared with the defect structure of an as-grown crystal. The transient results for the interface deflection as well as the point-defect distribution show good qualitative agreement with the experimental results. (C) 2004 Elsevier B.V. All rights reserved.