Rapid Thermal Chemical Vapor Deposition (RTCVD) is a promising technology for thin film deposition in advanced cluster tool systems. It is well known that, if left uncompensated, excessive heat losses that occur around the wafer edge can lead to temperature and deposition non-uniformities. Using polysilicon deposition on SiO2 as an example we have shown that deposition non-uniformity can be aggravated by absorptivity variations across the wafer. In this paper, we propose a novel approach to alleviate this problem. In this technique, the edge cooling effect is compensated by increasing the absorptivity of the substrate around its perimeter. This is achieved by etching a thin (width≈200μm) ring from the isolation oxide around the wafer perimeter prior to polysilicon deposition. During polysilicon deposition, the absorptivity of the silicon-oxide-polysilicon structure continually changes resulting in positive and negative feedback mechanisms in certain polysilicon thickness ranges determined by both modeling and experiments. However, this absorptivity always remains less than the constant absorptivity of the silicon-polysilicon ring along the perimeter which is referred to here as the Constant Absorptivity Ring (CAR). The higher absorptivity of CAR shields edge cooling effects from the rest of the wafer. In this paper, we present the results of our experiments conducted to demonstrate the effectiveness of CAR in improving uniformity of polysilicon. We show that by using CAR uniform films can be obtained in a reactor which otherwise delivers a polysilicon non-uniformity of 30-40%.