The uniformity of the thickness of a deposition layer, generated by a chemical vapor deposition (CVD) process, on a semiconductor wafer is enhanced by providing an undercoating on the deposition chamber. The undercoating is formed at a deposition rate significantly faster than the deposition rate of the material on the wafer. A thin precoat is typically formed over the undercoating. Another method of providing uniformity of thickness includes altering the temperature of the wafer or a series of wafers to alter the deposition rate. The alteration of the temperature of the wafer may include the use of a temperature ramp which increases or decreases the deposition temperature between two or more wafers in a series of wafers.