reduce radiation heat loss from process chamber 112 also the small aperture size keeps down the number of particles entering process chamber 112 and allows for easier maintenance of the isothermal temperature environment fig3 a and 3b show an embodiment of the heating assembly of the present invention heating assembly 118 includes heating member or plate 120 at least one heat source 122 and a coupling mechanism 124 in a preferred embodiment heating assembly 118 may be positioned suspended within process chamber 112 in a cantilevered relationship on a wall of process chamber 112 alternatively heating assembly 118 may rest on mounts emanating up from a floor of process chamber 112 heating plate 120 may have a large mass relative to wafer 116 and may be fabricated from a material such as silicon carbide quartz inconel aluminum steel or any other material that will not react at high processing temperatures with any ambient gases or with wafer 116 arranged on a top surface of heating plate 120 may be wafer supports 126 in a preferred embodiment wafer supports 126 extend outward from the surface of heating member 120 to support the single wafer 116 wafer supports 126 are sized to ensure that wafer 116 is held in close proximity to heating member 120 for example wafer supports 126 may each have a height of between about 50 u03bcm and about 20 mm preferably about 2 mm to about 8 mm the present invention includes at least three wafer supports 116 to ensure stability however the total contact area between wafer supports 126 and wafer 116 is less than about 350 mm 2 preferably less than.