Evaporation vessel apparatus and method

Abstract

Disclosed is a method of providing a constant concentration of a metal-containing precursor compound in the vapor phase in a carrier gas. Such method is particularly useful in supplying a constant concentration of a gaseous metal-containing compound to a plurality of vapor deposition reactors.

What is claimed is: 
     
         1 . An apparatus for delivering a substantially constant concentration of a vaporized precursor compound in a carrier gas to a plurality of vapor deposition reactors, comprising: 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, and a gas exit line in fluid communication between the gas outlet and a plurality of vapor deposition reactors; a carrier gas control valve in the carrier gas feed line; a concentration transducer for sensing a concentration of the vaporized precursor compound in a gaseous mixture in the gas exit line; a controller in electrical connection with the carrier gas control valve and the concentration transducer; the concentration transducer adapted to send a sensed concentration to the controller; the controller adapted to compare the sensed concentration (c) with a reference concentration (c 0 ) to provide a concentration differential (c−c 0 ), the controller adapted to generate a signal utilizing the concentration differential and to transmit the signal to the carrier gas control valve wherein the signal acts on the carrier 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. 
     
     
         2 . The apparatus of  claim 1 , wherein a second gas control valve is present in the gas exit line. 
     
     
         3 . The apparatus of  claim 1 , wherein the gas exit line further comprises a pressure release valve. 
     
     
         4 . The apparatus of  claim 1 , wherein the concentration transducer is an acoustic concentration transducer. 
     
     
         5 . The apparatus of  claim 1 , wherein the gas exit line further comprises a pressure transducer and wherein the pressure transducer is electrically connected to the controller. 
     
     
         6 . The apparatus of  claim 1 , wherein the controller is configured maintain the substantially constant concentration of the vaporized precursor compound in the gaseous mixture in the gas exit line with steps selected from the group consisting of:
 1) sensing the concentration of vaporized precursor compound in the gaseous mixture with the concentration transducer in the gas exit line,   comparing the sensed concentration with a reference concentration to provide a concentration differential,   generating a signal in the controller utilizing the concentration differential,   transmitting the signal to the gas control valve wherein the signal is configured to adjust the gas control valve to adjust the 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) sensing a temperature of the vaporized precursor compound within the evaporation vessel with a temperature sensing means,   comparing the sensed temperature with a reference temperature to provide a temperature differential,   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 the 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; and     3 ) a combination of (1) and (2).   
     
     
         7 . The apparatus of  claim 6 , wherein the temperature sensing means comprises:
 a temperature sensor.