An apparatus and method for processing a substrate is provided. The apparatus comprises a reaction chamber, a substrate holder within the chamber, and first and second injector components. The reaction chamber has an upstream end and a downstream end, between which the substrate holder is positioned. The substrate holder is configured to support a substrate so that the substrate is within a plane extending generally toward the upstream and downstream ends. The first injector component is at the upstream end of the chamber and is configured to inject a first thin gas curtain toward a substrate supported by the substrate holder. The first injector component is configured to inject the first curtain generally along a first plane that is parallel to a first side of the substrate. The second injector component is configured to inject a second thin gas curtain toward the first side of the substrate. The second injector component is configured to inject the second gas curtain generally along a second plane oriented at an angle with respect to the first plane. The angled flows of source gases have reduced interdiffusion volume above the substrate, preferably resulting in deposition substantially along a line extending across the center of the substrate. The substrate can be rotated during deposition to produce a substantially uniform film on the substrate.