Abstract: A chemical vapor deposition reactor including a wafer boat with a vertical stack of horizontally oriented susceptors serving as thermal plates and each having pins extending upward for suspending a wafer between a pair of susceptors. Reactant gas injector and exhaust apparatus are positioned to concentrate a forceful supply of reactant gas across each wafer at a speed in excess of 10 cm/sec. The pressure is held in the range of 0.1 to 5,000 mTorr. The forceful gas flow avoids gas depletion effects, thinning the boundary layer and resulting in faster delivery of reactants to substrate surfaces, resulting in surface rate reaction limited operation. A plurality of individually controllable heaters are spaced vertically around the sides of the boat. Temperature sensors monitor the temperature along the boat height and provide input to a controller for adjusting the heater drive to optimize the temperature uniformity.