Method and apparatus

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 gas control means in the carrier gas feed line; a sensing means in the gas exit line for sensing a concentration of the vaporized precursor compound in the gaseous mixture in the gas exit line; means for comparing the sensed concentration (c) with a reference concentration (c o ) to provide a concentration differential (c−c o ); signal generating means for generating a signal in a controller utilizing the concentration differential; and a means for transmitting the signal to the gas control means wherein the signal adjusts the gas control means 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 sensing means in the gas exit line for sensing concentration is an acoustic concentration transducer. 
     
     
         5 . The apparatus of  claim 1  wherein the gas exit line further comprises a pressure transducer. 
     
     
         7 . 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, a gas exit line in fluid communication between the gas outlet and a plurality of vapor deposition reactors, and a temperature sensing means situated within the evaporation vessel so as to sense temperature of precursor compound; means for comparing the sensed temperature (T) with a reference temperature (T o ) to provide a temperature differential (T−T o ); a gas control means in the carrier gas feed line; means for generating a signal in a pressure controller utilizing the temperature differential; and a means for transmitting the signal to the gas control means wherein the signal adjusts the gas control means 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. 
     
     
         7 . The apparatus of claim  6  wherein a second gas control valve is present in the gas exit line. 
     
     
         8 . The apparatus of claim  6  wherein the gas exit line further comprises a pressure transducer. 
     
     
         9 . The apparatus of claim  6  wherein the gas exit line further comprises a pressure release valve. 
     
     
         10 . The apparatus of claim  6  wherein the gas exit line comprises a sensing means in the gas exit line for sensing a concentration of the vaporized precursor compound in the gaseous mixture in the gas exit line.