Method and apparatus for dry/catalytic-wet steam oxidation of silicon

Abstract

A configuration of various chemical compound generators coupled to a furnace provides the environment for formation of extremely thin oxides of silicon on a wafer. Dichloroethylene is reacted with oxygen in a first heated reaction chamber and reaction products therefrom are diluted with a gas such as nitrogen and then introduced into a vertically oriented furnace maintained at an elevated temperature and having rotating wafers therein. Hydrogen and oxygen are catalytically reacted to form steam in a second heated reaction chamber, the steam is diluted with a gas such as nitrogen and introduced into the vertical diffusion furnace. In a further aspect of the present invention, MOSFETs having gate dielectric layers of extremely thin oxides of silicon are formed.

What is claimed is:  
     
         1 . An apparatus, comprising: 
 a furnace having an opening at one end to receive a wafer container, and having a showerhead gas receiver at a second end;    a first reaction chamber adapted to receive 1,2-dichloroethylene and oxygen, and having a first output port;    a second reaction chamber adapted to receive O 2 , H 2 , and N 2 , the second reaction chamber having a catalyst therein, and a second output port; and    a source of diluting gas;    wherein the source of diluting gas and the first output are coupled to the showerhead through a first pathway, and the second output port is coupled to the showerhead through a second pathway.    
     
     
         2 . The apparatus of  claim 1 , further comprising a bubbler containing liquid 1,2-dichloroethylene coupled to the first reaction chamber.  
     
     
         3 . The apparatus of  claim 1 , further comprising a push mechanism, coupled to the furnace, adapted to provide rotational velocity to the wafer container.  
     
     
         4 . The apparatus of  claim 1 , wherein the second pathway comprises stainless steel tubing fitted with a thermal jacket for maintaining a desired temperature.  
     
     
         5 . The apparatus of  claim 1 , wherein the catalyst comprises a material that promotes the formation of steam from O 2  and H 2  without flaming.  
     
     
         6 . The apparatus of  claim 1 , wherein the diluting gas comprises N 2 .  
     
     
         7 . The apparatus of  claim 1 , further comprising an H 2  detector coupled to the second output port.  
     
     
         8 . A method of forming a dielectric layer on a surface of a substrate, comprising: 
 maintaining at least one substrate in a furnace at a temperature of approximately 625° C.;    rotating the at least one substrate;    providing diluted HCl, CO 2 , and O 2  to a first end of the furnace; and    providing diluted steam the first end of the furnace.    
     
     
         9 . The method of  claim 8 , wherein diluted HCl, CO 2 , and O 2  is diluted with N 2 .  
     
     
         10 . The method of  claim 8 , wherein diluted steam is diluted with N 2 .  
     
     
         11 . The method of  claim 8 , further comprising reacting 1,2-dichloroethylene and oxygen to produce at least HCl and CO 2 .  
     
     
         12 . The method of  claim 8 , further comprising catalytically reacting O 2  and H 2  in the presence of N 2  at a temperature of approximately 500° C.  
     
     
         13 . The method of  claim 8 , wherein the at least one substrate comprises a silicon wafer.  
     
     
         14 . The method of  claim 8 , wherein rotating the at least one substrate comprises rotating at approximately 3 rpm.  
     
     
         15 . The method of  claim 8 , wherein the at least one substrate comprises at least 100 silicon wafers each having a diameter of substantially 200 mm; and wherein the wafers are rotated at approximately 3 rpm.  
     
     
         16 . The method of  claim 8 , wherein diluted HCl, CO 2 , and O 2  are provided to the furnace at atmospheric pressure.  
     
     
         17 . The method of  claim 8 , wherein providing diluted HCl, CO 2 , and O 2  is substantially stopped prior to providing diluted.  
     
     
         18 . The method of  claim 8 , wherein the dielectric layer is an oxide of silicon having a 3σ uniformity of 0.5 angstroms.  
     
     
         19 . The method of  claim 8 , wherein the furnace is vertically oriented and the first end is the top end.  
     
     
         20 . A method of making a field effect transistor, comprising: 
 providing oxygen and nitrogen to a furnace;    pushing one or more wafers into the furnace;    rotating the one or more wafers at approximately 3 rpm    providing HCl, CO 2 , N 2 , and O 2  to the furnace and maintaining a temperature of approximately 625° C.;    providing N 2  and steam, at approximately 180° C., to the furnace;    removing the one or more wafers from the furnace;    patterning at least one gate electrode on the one or more wafers; and    forming source/drain terminals substantially adjacent the gate electrode.    
     
     
         21 . The method of  claim 20 , further comprising nitridizing an oxide layer on a surface of the wafer prior to patterning at least one gate electrode on the wafer.  
     
     
         22 . The method of  claim 20 , wherein providing HCl, CO 2 , N 2 , and O 2  continues for approximately 2 minutes.  
     
     
         23 . The method of  claim 20 , wherein providing steam and N 2 , continues for approximately 6 minutes.  
     
     
         24 . The method of  claim 20 , further comprising annealing the one or more wafers.  
     
     
         25 . The method of  claim 24 , wherein annealing comprises maintaining the one or more wafers at approximately 625° C., in a nitrogen ambient for approximately 30 minutes.  
     
     
         26 . An oxide furnace system, comprising 
 a furnace having a gas inlet at a first end, and a wafer receiving port at a second end;    a dry chlorinated oxygen generator coupled to the gas inlet;    a catalytic steam generator coupled to the gas inlet;    a push mechanism, aligned with the wafer receiving port, adapted to provide linear and rotational velocity to a plurality of wafers; and    a temperature-controlled pathway disposed between the catalytic steam generator and the gas inlet;    wherein the dry chlorinated oxygen generator and the catalytic steam generator are spaced apart from the furnace and coupled to the gas inlet of the furnace by plumbing.    
     
     
         27 . The oxide furnace of  claim 26 , further comprising a furnace controller coupled to the furnace.  
     
     
         28 . The oxide furnace of the  claim 26 , further comprising an H 2  detector coupled to the output of the catalytic steam generator.  
     
     
         29 . The oxide furnace of  claim 26 , further comprising an alarm coupled to the H 2  detector.