Abstract: There is a slotted cantilever diffusion tube system with a temperature insulating baffle system and a distributed gas injector system. Uniquely, there is an enhanced system that decreases the defects of wafers due to temperature, pressure, and concentration fluctuations in a low pressure chemical vapor deposition (LPCVD) process for fabricating IC wafers. Specifically, there is a cantilevered diffusion quartz tube system (12, 14) that has at least one temperature and pressure barrier baffle (28) placed between the lower temperature end (27) of the tube and the wafers under process (18). Additionally, there are at least two deposition gas injection exhaust ports (30, 32, 34) distributed along the length of the quartz tube near the wafers to assure that there is a relatively uniform concentration of diffusion gas in the heating chamber (17).