Patent ID: 7390366

Claim:
An apparatus for chemical vapor deposition (CVD) comprising: a reaction chamber; a wafer supporting member for mounting a wafer in the reaction chamber; a reaction gas supplying unit with at least one gas outlet oriented to supply processing gas to the reaction chamber so that the processing gas impinges on a wafer from above the wafer; a purge gas supplying unit for supplying purge gas to the reaction chamber; a ring-shaped gas outlet positioned in the vicinity of the wafer supporting member, and extending peripherally around the wafer supporting member; and a shielding layer positioned at an entrance of the gas outlet and extending peripherally around the wafer supporting member, said shielding layer separating the gas outlet into an upper part for reaction gas flow and a lower part for purge gas flow so that the processing gas and the purge gas may not be mixed during exhaustion of the gases, wherein a distal end of the shielding layer extends toward the wafer supporting member, so that the distal end of the shielding layer is closer to the wafer supporting member than the gas outlet.