A gas mixing system for semiconductor fabrication includes a mixing block. The mixing block defines a gas mixing chamber, a first gas channel fluidly coupled to the gas mixing chamber at a first exit location, and a second gas channel fluidly coupled to the gas mixing chamber at a second exit location, wherein the first exit location is diametrically opposite the second exit location relative to the gas mixing chamber and the second gas channel has a bend of 90 degrees or less between an entrance of the second gas channel and the second exit location.