Patent ID: 8283262

Claim:
A method for depositing a layer on a semiconductor wafer using chemical vapor deposition (CVD), the method comprising: providing a chamber having an inlet opening and an outlet opening and a channel joining the inlet opening and the outlet opening, wherein the channel is bounded at the bottom by a plane and at the top by a window transmissive to thermal radiation, disposing a semiconductor wafer so that a surface of the semiconductor lies in the plane, wherein the window has a center region covering the semiconductor wafer and an edge region disposed outside the center region and not covering the semiconductor wafer, wherein a distance between the plane and the window varies across the chamber, the distance being greater at the edge region than at the center region, and wherein a tangent applied to a radial profile of the distance at a boundary between the center region and the edge region forms an angle with the plane of not less than 15° and not more than 25°; and conducting a deposition gas through the channel from the gas inlet opening over the semiconductor wafer to the gas outlet opening, wherein a speed at which the deposition gas is conducted varies over the semiconductor wafer according to the varying distance between the plane and the window.