MOCVD process using ozone as a reactant to deposit a metal oxide barrier layer

Abstract

A process is disclosed for creating a barrier layer on a silicon substrate of an in-process integrated circuit. The process uses MOCVD to form a metal oxide film. The source gas is preferably an organometallic compound. Ozone is used as an oxidizing agent in order to react with the source gas at a low temperature and fully volatilize carbon from the source gas. The high reactivity of ozone at a low temperature provides a more uniform step coverage on contact openings. The process is used to create etch stop layers and diffusion barriers.

1 . A process for creating a barrier layer on a semiconductor substrate, comprising: 
 forming a discrete region in the semiconductor substrate;    disposing the semiconductor substrate in a reaction chamber;    heating the semiconductor substrate in a range from about 100° C. to about 1000° C.;    introducing an inert carrier gas into the reaction chamber;    introducing a vaporized organometallic source gas and ozone gas into the reaction chamber, the organometallic source gas being a compound comprising metal, carbon, and hydrogen; and    introducing additional ozone gas into the reaction chamber to react the source gas with the ozone gas and to deposit from the reaction a metal oxide film on at least a portion of a surface of the discrete region as a barrier layer.    
   
   
       2 . The process of  claim 1 , further comprising: 
 halting the introduction of the source gas and ozone gas to the reaction chamber;    purging the reaction chamber; and    removing the semiconductor substrate from the reaction chamber.    
   
   
       3 . The process of  claim 1 , wherein the barrier layer functions as a diffusion barrier and is formed on a surface of an opening in an oxide layer that has been formed over the underlying discrete region.  
   
   
       4 . The process of  claim 1 , wherein the barrier layer functions as a diffusion barrier and prevents interdiffusion of the discrete region with a later deposited structure.  
   
   
       5 . The process of  claim 1 , wherein the reaction chamber is pressurized in a range from about 0.1 torr to about 1 torr.  
   
   
       6 . The process of  claim 1 , wherein the barrier layer is electrically conductive.  
   
   
       7 . The process of  claim 1 , wherein the metal oxide film is deposited at a temperature in a range from about 300° C. to about 1000° C.  
   
   
       8 . A process for creating a barrier layer on a semiconductor substrate, comprising: 
 forming a discrete region in the semiconductor substrate;    disposing the semiconductor substrate in a reaction chamber;    heating the semiconductor substrate in a range from about 100° C. to about 1000° C.;    introducing an inert carrier gas into the reaction chamber;    introducing a vaporized organometallic source gas and ozone gas into the reaction chamber, the organometallic source gas being a compound comprising metal, carbon, and hydrogen;    introducing additional ozone gas into the reaction chamber to react the source gas with the ozone gas and to deposit from the reaction a metal oxide etch stop film on at least a portion of a surface of the discrete region;    forming an oxide layer over the metal oxide etch stop film, and    etching an opening in the oxide layer with an etchant, wherein the metal oxide etch stop film substantially prevents the etchant from etching the discrete region.    
   
   
       9 . The process of  claim 8 , wherein the metal oxide etch stop film is selected from the group consisting of a conductive metal oxide film, a Ru oxide film, and an aluminum oxide film.  
   
   
       10 . The process of  claim 8 , wherein the source gas is selected from the group consisting of aluminum trimethane, titanium tetramethane, tantalum, trimethyl aluminum hydrate, a Ru metalorganic precursor, and dimethyl aluminum hydrate.  
   
   
       11 . The process of  claim 8 , wherein the metal oxide etch stop film is deposited at a temperature in a range from about 300° C. to about 1000° C.  
   
   
       12 . A process for creating a barrier layer on a semiconductor substrate, comprising: 
 forming a discrete region in the semiconductor substrate;    exposing a surface of the discrete region to a metal-containing source gas and to ozone gas to react the source gas with the ozone gas to deposit a barrier layer comprising aluminum oxide on the surface of the discrete region;    forming an oxide layer over the barrier layer;    etching an opening in the oxide layer with an etchant, wherein the barrier layer functions as an etch stop to substantially prevent the etchant from contacting the discrete region; and    removing the barrier layer with a solution of phosphoric acid.    
   
   
       13 . The process of  claim 12 , wherein the barrier layer is deposited at a temperature in a range from about 300° C. to about 1000° C.  
   
   
       14 . A deposition method comprising: 
 providing a substrate; and    depositing upon the substrate a metal oxide formed while reacting source and oxidizing gases such that the metal in the metal oxide is oxidized prior to deposition.    
   
   
       15 . The deposition method of  claim 14 , wherein the substrate comprises: 
 a semiconductive material;    an electrically active region therein; and    a surface thereon a portion of which is also a surface on the electrically active region that is in contact with the metal oxide.    
   
   
       16 . The deposition method of  claim 14 , wherein depositing the metal oxide upon the substrate is performed in a chamber at a pressure in a range from about 0.1 torr to about 1 torr.  
   
   
       17 . The deposition method of  claim 14 , wherein the source and oxidizing gases include a source gas selected from the group consisting of aluminum trimethane, titanium tetramethane, a vaporized tantalum in the form of an organometallic compound, trimethyl aluminum hydrate, a Ru metalorganic precursor, and dimethyl aluminum hydrate.  
   
   
       18 . A deposition method comprising: 
 providing a semiconductor substrate having a top surface and an electrically active region extending from the top surface into the semiconductor substrate; and    depositing upon the electrically active region, in a chamber at a pressure in a range from about 0.1 torr to about 1 torr, a metal oxide that is formed while reacting a source gas and an oxidizing gas such that the metal in the metal oxide is oxidized prior to deposition, the source gas selected from the group consisting of aluminum trimethane, titanium tetramethane, a vaporized tantalum in the form of an organometallic compound, trimethyl aluminum hydrate, a Ru metalorganic precursor, and dimethyl aluminum hydrate.