Multi-gas distribution injector for chemical vapor deposition reactors

An injector for a chemical vapor deposition reactor, the injector defining an interior surface facing in a downstream direction and having a horizontal extent, the injector comprising:

• a plurality of unitary plate members arranged in a stacked relationship along an axis extending generally in an upstream to downstream direction, such that a downstream side of one of the plate members confronts an upstream side of another one of the plate members and the confronting plate members define a first chamber between them, a first one of the unitary plate members having a plurality of first projections integral with that plate member and extending into the first chamber towards a second one of the plate members so that the first projections of the first plate member sealingly engage the second plate member, the first and second plate members defining first gas passages extending in the upstream to downstream direction through the first projections and through the first and second plate members but not communicating with the first chamber, each of the first gas passages having a downstream end communicating with one of a plurality of first gas inlets open to the interior surface.