A process for depositing a thin film material on a substrate, comprising simultaneously directing a series of gas flows from an output face of a delivery head of a thin film deposition system toward the substrate surface, and wherein the series of gas flows comprises at least a first reactive gaseous material, an inert purge gas, and a second reactive gaseous material, wherein the first reactive gaseous material is capable of reacting with the substrate surface treated with the second reactive gaseous material, wherein the delivery head comprises: (a) at least a first, a second, and a third inlet port for receiving the first reactive gaseous material, the second reactive gaseous material, and the inert purge gas, respectively; (b) at least one exhaust port for exhausting waste gases; (c) an output face in proximity to the substrate surface comprising a plurality of elongated openings; wherein: (i) each of the inlet ports (14, 16, 18) is independently connected, respectively, to at least one first, second, and third elongated output opening for supplying the respective gaseous materials (O, M, I) to the substrate; and (ii) the at least one exhaust port is connected to at least two elongated exhaust openings each having an associated pressure, wherein the elongated exhaust openings are disposed such that at least a first, a second, or a third elongated output opening is located between the at least two elongated exhaust openings; and wherein a substantially uniform distance between the output face and the substrate surface is maintained at least in part by pressure generated due to flows of one or more of the gaseous materials (O, M, I) from the elongated output openings to the substrate surface and wherein the difference between atmospheric pressure and the average pressure of the elongated exhaust openings measured in Pascals is at least two times the average weight per unit area of the substrate, also measured in Pascals. (a) at least a first, a second, and a third inlet port for receiving the first reactive gaseous material, the second reactive gaseous material, and the inert purge gas, respectively; (b) at least one exhaust port for exhausting waste gases; (c) an output face in proximity to the substrate surface comprising a plurality of elongated openings; wherein: (i) each of the inlet ports (14, 16, 18) is independently connected, respectively, to at least one first, second, and third elongated output opening for supplying the respective gaseous materials (O, M, I) to the substrate; and (ii) the at least one exhaust port is connected to at least two elongated exhaust openings each having an associated pressure, wherein the elongated exhaust openings are disposed such that at least a first, a second, or a third elongated output opening is located between the at least two elongated exhaust openings; and (i) each of the inlet ports (14, 16, 18) is independently connected, respectively, to at least one first, second, and third elongated output opening for supplying the respective gaseous materials (O, M, I) to the substrate; and (ii) the at least one exhaust port is connected to at least two elongated exhaust openings each having an associated pressure, wherein the elongated exhaust openings are disposed such that at least a first, a second, or a third elongated output opening is located between the at least two elongated exhaust openings; and