Vapor Concentration Control
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Vapor concentration control of precursors provide substantial improvement in stabilizing MOCVD processes. By measuring a precursor partial pressure in a downstream line with a Non Dispersive Infrared (NDIR) technology and controlling its total pressure, a precursor concentration can be kept constant. This precursor concentration control is validated as a practical method against a temperature fluctuation of a cylinder bath and a failure of reaching a saturation pressure in a cylinder.