Abstract: A reaction chamber for a controlled reaction on a reaction surface of a sample provides for controlled distribution of radiant energy over the reaction surface to offset radiant heat loss of the sample, and establishes uniform distribution of reactant flow on the sample. A lamp housing supplies radiant energy over the sample, which absorbs at least a component of the radiant energy. A support member which supports the sample within the reaction chamber is formed of a material which is essentially transparent to the radiant energy so that it does not behave as a susceptor. An array of lamps, is mounted with the reaction chamber so that direct radiant energy is transmitted through a window to the reaction surface of the sample. A reflecting surface on the housing includes a lamp seat for each lamp in the array with an individually specified position, curvature and tilt with respect to the reaction surface.

Abstract: A method for inducing a reaction in a reaction chamber of a reactive carrier having a first specific heat, on a reaction surface of a substrate. The method comprises the steps of supporting the substrate in the reaction chamber. Next, the substrate is heated to a reaction temperature, so that the reaction surface has an essentially balanced temperature distribution. The reactive carrier is mixed with an inert gas having a second specific heat to form a reaction mixture, wherein the second specific heat is lower than the first specific heat. Finally, the reaction mixture is supplied into the chamber so that it flows over the surface of the substrate. Because the inert gas has a lower specific heat than the carrier, the overall specific heat of the reaction mixture is reduced. With a lower specific heat, less heat is transferred from the wafer into the reaction mixture. This reduces convective heat loss and thermal gradients in the substrate.