Radiative heat windows and wafer support pads in vapor etch reactors

An apparatus may include: (a) a processing chamber including chamber walls and a chamber heater configured to heat the chamber walls; and (b) a pedestal positioned within the chamber interior and including: (i) a substrate heater having a plurality of light emitting diodes (LEDs), (ii) a window positioned above the substrate heater comprising a material transparent to light from the LEDs, and (iii) three or more substrate support pads, each substrate support pad having a substrate support surface vertically offset from the window and configured to support a substrate such that the window and the substrate supported by the three or more substrate support pads are offset by a nonzero distance.