A susceptor carrying semiconductor wafers for processing is suspended from a compliant attachment at its upper end and is lowered into a reaction chamber for processing. At the completion of processing, the susceptor is withdrawn vertically to permit a robot to unload the processed wafers and load unprocessed wafers. In order to fix the position of the susceptor during the loading operations, a support carriage is moved into position to engage the lower end of the susceptor. Noxious and corrosive chloride vapors are simultaneously withdrawn from the reaction chamber by a vacuum line attached to the support carriage.