It has been demonstrated that 200 mm diameter semi-insulating (SI) GaAs single crystals can be grown by an upscaled proprietary VGF method successfully used for commercial crystal growth up to 150 mm in the past. First results of structural and electrical characterization of wafers made from these crystals will be presented. They are similar to those known for state-of-the-art 150 mm SI GaAs VGF/VB crystals. (C) 2002 Elsevier Science B.V. All rights reserved.