LOW MASS SUSCEPTOR

A wafer susceptor for semiconductor processing devices, having a thermal mass which is close to that of the wafer. The similarity between the thermal masses of the susceptor and wafer enables a higher throughput and reduces temperature uniformities across the wafer. The low-mass susceptor may be made of a solid, thin disk with or without a central wafer support recess. A wafer temperature sensing aperture may be provided in the center of the susceptor. Alternatively, a low-mass susceptor is formed with an open-celled silicon carbide foam, with or without a thin skin of solid silicon carbide on the top forming a wafer support surface, or completely encapsulating the open-celled foam. The wafer is preferably supported on a plurality of pins extending upward from the susceptor. In a third embodiment, an ultra low-mass susceptor is formed as a ring with a central throughbore and a surrounding wafer support shelf below an outer ledge.