Abstract: A reaction system and process for uniformly heating semiconductor substrates and a device for supporting the same and direct conductive heating of IC wafers within a reactor are described. The substrate is held in direct contact with the heating source positioned within the reactor. The heat source is a thermal delivery module made of material such as solid silicon carbide, or high temperature material containing resistive heating elements. The heat is uniformly transferred to the walls of the module by a molten metal having a low melting point and high boiling point such as essentially indium or bismuth or a eutectic of indium and bismuth.