A system for depositing a thin film on a substrate, the system comprising:
- a reaction chamber, including an inlet for introducing a precursor gas into the reaction chamber;
- a shroud located within the reaction chamber, the shroud positioned such that the inlet is located outside of the shroud to introduce the precursor gas outside of the shroud, the shroud operably coupled to a secondary gas supply system configured to flow a secondary gas into the shroud, the shroud configured to direct the secondary gas towards a substrate, when the substrate is present in the reaction chamber and positioned proximal to a perimeter of the shroud, and so that the secondary gas exits the shroud along the perimeter and into the reaction chamber where the secondary gas mixes with the precursor gas;
- a radical generator operably coupled to the shroud, the radical generator configured to generate a gaseous radical species from the secondary gas and to introduce the gaseous radical species inside of the shroud, when the secondary gas is present and flowing;
- and
- a positioning system configured to alternately position the shroud over selected regions of the substrate, when the substrate is present in the reaction chamber, to thereby alternately expose the selected regions of the substrate to the gaseous radical species and the precursor gas multiple times, each exposure of to the precursor gas resulting in some of the precursor gas adsorbing on the selected regions of the substrate as an adsorbed precursor, and each subsequent exposure of the selected regions of the substrate to the gaseous radical species resulting in some of the radicals converting at least a portion of the adsorbed precursor to a product in the selected regions, whereby a thin film is formed in the selected regions of the substrate;
- and
- wherein the shroud further comprises a radical deactivation device including a deactivating surface extending outwardly from the perimeter of the shroud and facing an exposed surface of the substrate, when the substrate is present in the reaction chamber and positioned proximal to the perimeter, to create a gap, between the deactivating surface and the exposed surface of the substrate, through which the gaseous radical species flows as the secondary gas exits the shroud, the deactivating surface sized to allow time for substantial recombination or other deactivation of radicals present in the gaseous radical species as the gaseous radical species flows through the gap, prior to the secondary gas exiting the shroud, to thereby prevent the gaseous radical species from interacting with the precursor gas in the reaction chamber outside of the shroud.