A barrier layer is formed in an integrated circuit by providing a metal target near a ceiling of the chamber and a wafer support pedestal facing the target near a floor of the chamber. An intravenous catheter assembly has a catheter adapter and a needle hub, and the catheter adapter has an inner lumen. 5, wherein upon focusing, a first lens group and a fourth lens group are fixed with respect to an image plane, and a second lens group and a third lens group are moved along an optical axis. The distance detector receives the light beam reflected from an object and develops an output signal having a value representing the distance of the object from the distance detector.