Patent ID: 8501266

Claim:
A method of depositing a film on a substrate, comprising: (a) providing an evaporation vessel comprising a chamber containing a precursor compound to be vaporized, the evaporation vessel having a gas inlet and a gas outlet, a carrier gas feed line in fluid communication with the gas inlet, a gas control valve in the gas feed line, and a gas exit line in fluid communication between the gas outlet and a plurality of vapor deposition reactors, the gas exit line having a pressure transducer and a concentration transducer, each of the gas control valve, pressure transducer and concentration transducer in electrical connection with a controller; (b) conveying a gaseous mixture comprising vaporized precursor compound and a carrier gas to the plurality of vapor deposition reactors; (c) maintaining a substantially constant concentration of the precursor compound in the gaseous mixture by the steps selected from the group consisting of: (1) sensing a concentration of the vaporized precursor compound in the gaseous mixture in the gas exit line; comparing the sensed concentration (c) with a reference concentration (c o ) to provide a concentration differential (c−c o ); generating a signal in the controller utilizing the concentration differential; transmitting the signal to the gas control valve wherein the signal adjusts the gas control valve to adjust total pressure within the evaporation vessel in order to maintain a substantially constant concentration of the vaporized precursor compound in the gaseous mixture in the gas exit line; (2) providing the evaporation vessel with a temperature sensing means, the temperature sensing means located so as to sense temperature of the precursor compound; sensing the temperature of the precursor compound; comparing the sensed temperature (T) with a reference temperature (T o ) to provide a temperature differential (T−T o ); generating a signal in the controller utilizing the temperature differential; transmitting the signal to the gas control valve wherein the signal adjusts the gas control valve to adjust total pressure in the evaporation vessel in order to maintain a substantially constant concentration of the vaporized precursor compound in the gaseous mixture in the gas exit line; and (3) a combination of (1) and (2); and (d) subjecting the gaseous mixture to conditions in the plurality of deposition reactors sufficient to deposit a film.