Semiconductor device, method of forming epitaxial film, and laser ablation device

Abstract

The present invention provides a semiconductor device comprising a single-crystal silicon substrate; and a single-crystal oxide thin film having a perovskite structure formed through epitaxial growth on the single-crystal silicon. substrate. The single-crystal oxide thin film is directly in contact with a surface of the single-crystal silicon substrate, and contains a bivalent metal that is reactive to silicon.

What is claimed is:  
     
         1 . A semiconductor device comprising: 
 a single-crystal silicon substrate; and    a single-crystal oxide thin film having a perovskite structure formed through epitaxial growth on the single-crystal silicon substrate, said single-crystal oxide thin film being directly in contact with a surface of the single-crystal silicon substrate, and containing a bivalent metal that is reactive to silicon.    
     
     
         2 . The semiconductor device as claimed in  claim 1 , wherein the bivalent metal is any bivalent metal but Sr.  
     
     
         3 . The semiconductor device as claimed in  claim 1 , wherein the single-crystal oxide thin film is selected from the group consisting of PbTiO 3 , PbZrO 3 , Pb(Zr, Ti)O 3 , (Pb, La)(Zr, Ti)O 3 , BaTiO 3 , and (Ba, Sr)TiO 3 .  
     
     
         4 . A semiconductor device comprising: 
 a single-crystal silicon substrate;    a single-crystal oxide thin film having a perovskite structure formed through epitaxial growth on the single-crystal silicon substrate; and    an amorphous silicon layer interposed between the single-crystal silicon substrate and the single-crystal oxide thin film.    
     
     
         5 . A semiconductor device comprising: 
 a single-crystal silicon substrate;    a first single-crystal oxide thin film having a sodium chloride structure formed through epitaxial growth on the single-crystal silicon substrate; and    a second single-crystal oxide thin film having a perovskite structure formed through epitaxial growth on the first single-crystal oxide thin film,    said first single-crystal oxide thin film being selected from the group consisting of CaO, SrO, and BaO.    
     
     
         6 . The semiconductor device as claimed in  claim 4 , wherein the single-crystal oxide thin film contains a bivalent metal selected from the group consisting of Sr, Ba, Pb, and La.  
     
     
         7 . The semiconductor device as claimed in  claim 4 , wherein the single-crystal oxide thin film is selected from the group consisting of PbTiO 3 , PbZrO 3 , Pb(Zr, Ti)O 3 , (Pb, La) (Zr, Ti)O 3 , BaTiO 3 , (Ba, Sr)TiO 3 , and SrTiO 3 .  
     
     
         8 . A semiconductor device comprising: 
 a single-crystal silicon substrate;    a first single-crystal oxide thin film having a sodium chloride structure formed through epitaxial growth on the single-crystal silicon substrate;    a second single-crystal oxide thin film having a perovskite structure formed through epitaxial growth on the first single-crystal oxide thin film; and    an amorphous layer formed between the single-crystal silicon substrate and the first single-crystal oxide thin film.    
     
     
         9 . The semiconductor device as claimed in  claim 8 , wherein the first single-crystal oxide thin film is selected from the group consisting of MgO, CaO, SrO, and BaO.  
     
     
         10 . The semiconductor device as claimed in  claim 8 , wherein the second single-crystal oxide thin film is selected from the group consisting of PbTiO 3 , PbZrO 3 , Pb(Zr, Ti)O 3 , (Pb, La) (Zr, Ti)O 3 , BaTiO 3 , (Ba, Sr)TiO 3 , and SrTiO 3 .  
     
     
         11 . A method of forming an epitaxial film, comprising the steps of: 
 forming a plume by irradiating a target containing a bivalent metal carbonate with a laser beam;    developing a bivalent metal oxide film from the bivalent metal carbonate through epitaxial growth on a single-crystal silicon substrate set in a passage of the plume; and    heating a surface of the target with an independent heat source different from the laser beam, thereby producing a single-crystal oxide. epitaxial film.    
     
     
         12 . The method as claimed in  claim 11 , wherein the step of heating the surface of the target is performed at the same time as the irradiation with the laser beam.  
     
     
         13 . The method as claimed in  claim 11 , further comprising the step of heating the plume.  
     
     
         14 . The method as claimed in  claim 11 , wherein the step of heating the surface of the target is performed prior to the irradiation with the laser beam.  
     
     
         15 . The method as claimed in  claim 11 , wherein the step of heating the surface of the target is performed at such a temperature that the carbonate decomposes on the surface of the target.  
     
     
         16 . The method as claimed in  claim 11 , further comprising the step of forming an oxide film having a perovskite structure through epitaxial growth on the single-crystal oxide epitaxial film by irradiating another target with a laser beam.  
     
     
         17 . A laser ablation device comprising: 
 a processing chamber that is exhausted by an exhausting system;    a processed substrate that is held within the processing chamber;    a target that is provided in the processing chamber and faces the processed substrate;    an optical window that is provided in the processing chamber and corresponds to an optical path of the laser beam irradiating the target; and    a heat source that is provided in the processing chamber and covers a space between the processed substrate and the target.