Patent ID: 8226770

Claim:
An apparatus for depositing material on a surface of a wafer, the apparatus comprising: a deposition chamber; an inlet for a reactive process gas to form deposited material within the chamber; a susceptor plate extending across the deposition chamber and having a surface for supporting a wafer and a backside surface opposite the wafer supporting surface; an infrared temperature sensor facing the backside of the susceptor to provide a viewing area for the temperature sensor; and a layer comprising an oxide, a nitride, an oxynitride, or combinations thereof covering an area consisting of only a portion of the backside surface of the susceptor plate, wherein the layer has a radius less than a radius of the susceptor plate such that a portion of the backside surface of the susceptor plate is free of the layer, the layer being stable in the presence of a reactive process gas and effective to inhibit deposited material from forming a film on the layer.