Abstract: An apparatus and method for heating a substrate and associated rotatable susceptor in an epitaxial deposition reactor with an axially symmetric gas flow carrying deposition material include at least one chamber having a plurality of heat lamps. The chamber is generally symmetric with respect to an axis of the substrate. The chamber walls are coated to reflect light from the heat lamps. The outermost heat lamps can be energized to produce a higher temperature than the centrally located lamps to compensate for regions of the reactor which provide access to the substrate and, therefore, promote thermal losses. The spacing of the heat lamps may be varied to compensate for thermal non-uniformity of the heating cavity. The substrate may be rotated, on the rotatable susceptor, to average the thermal environment to which the substrate is exposed.