PRIMARY FLOW CVD APPARATUS AND METHOD

摘要

A chemical vapor deposition apparatus comprising a hot wall reaction tube, one or more reaction gas preheaters, a reaction gas exhaust outlet, and substantially eddy free reaction gas flow control means for passing reaction gases in a substantially laminar flow from a preheater to the exhaust outlet. The gas flow control means includes a tube flange positioned to be in a substantially eddy free relationship with the end of the wafer boat zone, the flange having a curved surface means extending from the end of the wafer boat zone to the outer tube for directing the reaction gas flow out of or into the reaction zone while maintaining the gas in a state of substantially laminar flow. One reaction gas preheater comprises a first heating tube having a removable baffle. A second reaction gas preheater comprises a two wall cylindrical heater with inner surface deformations. The two wall cylindrical heater and the heating tube each can have a plurality of gas injector ports with central axes positioned to cause immediate mixing of gases injected therefrom. An alternate reaction gas preheater comprises the passageway formed by concentric vacuum and reaction chamber tubes.