Abstract: A controlled diffusion environment capsule system (10) is used with a conventional tubular high temperature furnace (12) as employed in semiconductor manufacturing. The system (10) includes a cantilever boat loading apparatus (14) and a quartz diffusion capsule (16). Wafer carriers (20) support semiconductor wafers (22) concentrically with capsule (16) in closely spaced relationship for processing in the furnace (12). The diffusion capsule (16) is supported on a pair of quartz rods (24). A quartz injector tube (28) extends the length of the diffusion capsule (16). The injector tube (28) has three rows of high aspect-ratio apertures (30) extending along its length to disperse nitrogen or other inert gas uniformly across the surfaces (32) of the wafers (22).