Patent ID: 7846292

Claim:
A two-piece gas injector, comprising: a plate including an upper surface and a lower surface having a plurality of first injection holes to inject a gas from the lower surface directly to a reaction space; and a plurality of cylindrical nozzle modules combined with the upper surface of the plate, each of the plurality of nozzle modules including at least one second injection hole connected to corresponding one of the plurality of first injection holes to form a gas path therethrough so as to provide the gas from the plurality of second injection holes, wherein the upper surface of the plate includes a plurality of openings connected to corresponding ones of the plurality of first injection holes, wherein the plurality of nozzle modules are inserted into the plurality of openings, respectively, and wherein a diameter of each of the plurality of openings is greater than a diameter of corresponding one of the plurality of first injection holes, wherein the gas flows from the upper surface of the nozzle module comprising said second opening to the lower surface of the plate comprising said first opening, wherein the plurality of openings and the plurality of nozzle modules are combined with each other using a screw, respectively, wherein each of the plurality of first injection hole has one of a cylindrical hollow shape and a tapering hollow shape, wherein a diameter of each of the plurality of first injection holes is greater than a diameter of each of the plurality of second injection holes.