Quick Answer A quartz gas injector is a high-purity fused silica tube, ring, or multi-port manifold that delivers process gas into a diffusion, LPCVD, or CVD furnace at a defined location and hole pattern. It is not the process tube. The tube is the reaction chamber; the injector owns gas distribution. Film thickness and dopant uniformity along the wafer load depend on hole diameter, hole pitch, [...]