Method and apparatus for delivering precursors to a plurality of epitaxial reactor sites

Abstract

PURPOSE: To improve the evaporation efficiency of a raw material by mounting an element of a porous sintered metal having the pore size smaller than the size of the solid raw material to a port for introducing a carrier gas into a bubbler vessel. CONSTITUTION: The solid raw material 2 is housed in the bubbler vessel 1 and is heated by a mantle heater, etc. The carrier gas is introduced from the introducing port 9 into the vessel 1 to generate the saturation pressure of the raw material 2. This material is sent into a film forming chamber 10 of the CVD device from a leading out pipe 8. The element 11 of the porous sintered metal is mounted to this introducing port 9. The carrier gas is ejected to a wide range from the many fine pores of the element 11 to the circumferences thereof and is uniformly dispersed. The wider contact area of the raw material 2 with the carrier gas is taken and the sufficient saturated steam pressure is obtd. The back flow of the raw material 2 to the mass flow controller is obviated even if the pressure on the film forming chamber 10 side increases. The damaging of the controller 4 is thus prevented.

1 . A method for delivering an organometallic compound to a plurality of reactor sites, the method comprising the step of introducing a carrier gas into a container of the organometallic compound, picking up the compound in the gas to form a gaseous mixture, transporting the gaseous mixture to a reservoir and selectively distributing the gaseous mixture to one or more of a plurality of reactor sites, the method excluding the step of condensing the gaseous mixture.  
     
     
         2 . A method as claimed in  claim 1 , wherein the rate of flow of the carrier gas and the carrier gas/organometallic mixture is controllable.  
     
     
         3 . A method as claimed in  claim 1  or  claim 2  further comprising introducing a second source of carrier gas into the gaseous mixture after pick up of the organometallic compound.  
     
     
         4 . A method as claimed in  claim 3 , wherein the addition of the second source of carrier gas is monitored to maintain the vapour concentration below saturation.  
     
     
         5 . A method as claimed in any one of  claims 1  to  4  further comprising the step of heating the gaseous mixture.  
     
     
         6 . A method as claimed in any one of  claims 1  to  5  wherein the gaseous mixture is drawn under vacuum or by means of pressure differential from the reservoir to each of the reactor sites.  
     
     
         7 . A method as claimed in any one of the preceding claims wherein the pick up of organometallic compound in the carrier gas is kept constant.  
     
     
         8 . A method as claimed in  claim 7  wherein a constant pick up is achieved over flow rates ranging from 0 to 10 litres per minute.  
     
     
         9 . A method as claimed in any one of the preceding claims wherein the carrier gas is hydrogen.  
     
     
         10 . An apparatus for delivering an organometallic compound to a plurality of reactor sites, the apparatus comprising an inlet for introducing a carrier gas ( 2 ) into a container ( 1 ) of the organometallic compound, a reservoir for storage of the gaseous mixture of the compound and the carrier gas and an outlet for selectively distributing the gaseous mixture to one or more of a plurality of reactor sites ( 12 ,  14 ,  16 ,  18 ,  20 ), the apparatus excluding a condensor for condensation of the gaseous mixture.  
     
     
         11 . An apparatus as claimed in  claim 10 , wherein one or more mass flow controllers ( 4 ) are provided to control the rate of flow of the carrier gas and the carrier gaseous mixture through the apparatus.  
     
     
         12 . An apparatus as claimed in  claim 11  wherein a first mass controller ( 4 ) is positioned to control the rate of flow of carrier gas into the container ( 1 ).  
     
     
         13 . An apparatus as claimed in  claim 10 ,  11  or  12 , further comprising means for introduction of a second source of carrier gas into the gaseous mixture after pick up of the organometallic compound.  
     
     
         14 . An apparatus as claimed in  claim 13 , wherein a second mass flow controller ( 7 ) is provided to monitor the addition of the second source of carrier gas.  
     
     
         15 . An apparatus as claimed in  claim 14 , wherein the second mass flow controller ( 7 ) is linked to the first mass flow controller ( 4 ).  
     
     
         16 . An apparatus as claimed in any one of  claims 10  to  15  wherein the reservoir ( 9 ) is provided with a pressure controller ( 8 ).  
     
     
         17 . An apparatus as claimed in any one of  claims 10  to  16  wherein means is provided to allow the gaseous mixture to be drawn under vacuum or by means of a pressure differential from the reservoir ( 9 ) to each of the reactor sites ( 12 ,  14 ,  16 ,  18 ,  20 ).  
     
     
         18 . An apparatus as claimed in any one of  claims 10  to  17  wherein each reactor site ( 12 ,  14 ,  16 ,  18 ,  20 ) is provided with its own mass flow controller ( 12   a,    14   a,    16   a,    18   a,    20   a ) to determine the rate of entry of the gaseous mixture into the reactor.  
     
     
         19 . An apparatus as claimed in claim any one of the preceding claims wherein the container ( 1 ) of organometallic compound is a bubbler, the carrier gas being introduced into the bubbler by means of a dip pipe ( 3 ).  
     
     
         20 . An apparatus as claimed in  claim 19  wherein the bubbler is surrounded by a temperature controlled oil bath ( 5 ).  
     
     
         21 . An apparatus as claimed in  claim 19  or  claim 20  wherein the bubbler is provided with means ( 6 ) for monitoring the level of organometallic compound therein.  
     
     
         22 . A bubbler ( 100 ) comprising a container for precursor and a dip pipe ( 102 ) for passage of a carrier gas therethrough to pick up the precursor in the gas, wherein the bubbler includes one or more of the following features: 
 (a) a narrowing of the container at or near the base thereof to aid complete utilisation of the precursor therein; and    (b) one or more hollow members ( 104   a,    104 b,  104   c ) extending substantially perpendicularly to the dip pipe ( 102 ) and being in fluid communication therewith, each member having an opening ( 106 ) therein to aid pick up of the precursor.    
     
     
         23 . A bubbler as claimed in  claim 22 , wherein the base of the bubbler is provided with a narrowing.  
     
     
         24 . A bubbler as claimed in  claim 23 , wherein the base of the bubbler has a smaller vessel placed therein relative to the bubbler.  
     
     
         25 . A bubbler as claimed in  claim 23  or  claim 24  wherein the end of the dip pipe is positioned within the narrowing or smaller vessel.  
     
     
         26 . A bubbler as claimed in any one  claims 22  to  25  wherein the dip-pipe ( 102 ) is provided with one or more hollow members ( 104   a,    104   b,    104   c ) extending substantially perpendicularly therefrom.  
     
     
         27 . A bubbler as claimed in  claim 26 , wherein each hollow member ( 104   a,    104   b,    104   c ) is situated at the base of the dip pipe.  
     
     
         28 . A bubbler as claimed in  claim 26  or  claim 27 , wherein each member is provided with a plurality of holes ( 106 ) in one or more sides thereof.  
     
     
         29 . A bubbler as claimed in claims  26 ,  27  or  28  wherein the dip pipe is provided with a hollow cross at the base thereof.  
     
     
         30 . A bubbler as claimed in  claim 29  wherein each leg of the cross has a plurality of holes.  
     
     
         31 . A bubbler as claimed in  claim 30  wherein the holes are provided in the same side of each leg.