Shallow trench isolation regions made from crystalline oxides

Abstract

A method of manufacturing a semiconductor device that involves etching a trench in a semiconductor substrate, epitaxially growing a crystalline structure in the trench and forming semiconductor structures on either side of the crystalline structure. Crystalline oxides may include rare earth oxides, aluminum oxides or Perovskites.

What is claimed is: 
     
         1 . A method of forming a semiconductor structure, the method comprising:
 etching a trench into a semiconductor substrate;   forming a crystalline oxide layer in the trench, wherein the crystalline oxide fills an entire volume of the trench to form an epitaxial oxide structure, wherein said epitaxial oxide structure does not extend above a topmost planar surface of said semiconductor substrate; and   forming a first semiconductor structure and a second semiconductor structure on the semiconductor substrate, wherein the epitaxial oxide structure is located between the first semiconductor structure and the second semiconductor structure, and wherein the epitaxial oxide structure substantially electrically isolates the first and the second semiconductor structure.   
     
     
         2 . The method of  claim 1 , wherein the crystalline oxide comprises rare earth oxides. 
     
     
         3 . The method of  claim 2 , wherein the rare earth oxide is selected from the group consisting of cerium oxide (CeO 2 ), lanthanum oxide (La 2 O 3 ), yttrium oxide (Y 2 O 3 ), gadolinium oxide (Gd 2 O 3 ), europium oxide (Eu 2 O 3 ), and terbium oxide (Tb 2 O 3 ). 
     
     
         4 . The method of  claim 1 , wherein the crystalline oxide comprises a combination of rare earth oxides. 
     
     
         5 . The method of  claim 4 , wherein the combination of rare earth oxides is a binary oxide having the chemical formula ABO 3 , wherein A is a rare earth metal atom and B is a different rare earth metal atom. 
     
     
         6 . The method of  claim 1 , wherein the crystalline oxide comprises a perovskite material. 
     
     
         7 . The method of  claim 6 , wherein the perovskite material is selected from the group consisting of strontium titanate (SrTiO 3 ) and barium titanate (BaTiO 3 ). 
     
     
         8 . The method of  claim 1 , wherein the crystalline oxide is aluminum oxide (Al 2 O 3 ). 
     
     
         9 . The method of  claim 1 , wherein the crystalline oxide is an aluminum oxide compound. 
     
     
         10 . The method of  claim 9 , wherein the aluminum oxide compound is lanthanum aluminum (LaAlO 3 ). 
     
     
         11 . A semiconductor device comprising:
 a substrate;   a first semiconductor structure located on the substrate;   a second semiconductor structure located on the substrate; and   a crystalline oxide layer located between the first semiconductor structure and the second semiconductor structure, wherein a top surface of the crystalline oxide layer is substantially planar with a top surface of the substrate, and the crystalline oxide layer extends below the top surface of the substrate, wherein the crystalline oxide layer electrically isolates the first and the second semiconductor structure.   
     
     
         12 . The device of  claim 11 , wherein the crystalline oxide layer comprises rare earth oxides. 
     
     
         13 . The device of  claim 12 , wherein the rare earth oxide is selected from the group consisting of cerium oxide (Ce02), lanthanum oxide (La 2 0 3 ), yttrium oxide (Y 203), gadolinium oxide (Gd203), europium oxide (EU203), and terbium oxide (Tb203). 
     
     
         14 . The device of  claim 11 , wherein the crystalline oxide layer comprises a combination of rare earth oxides. 
     
     
         15 . The device of  claim 14 , wherein the combination of rare earth oxides is a binary oxide having the chemical formula AB03, wherein A is a rare earth metal atom and B is a different rare earth metal atom. 
     
     
         16 . The device of  claim 11 , wherein the crystalline oxide layer comprises a perovskite material. 
     
     
         17 . The device of  claim 16 , wherein the perovskite material is selected from the group consisting of strontium titanate (SrTi03) and barium titanate (BaTi03). 
     
     
         18 . The device of  claim 11 , wherein the crystalline oxide layer is aluminum oxide (Ah03). 
     
     
         19 . The device of  claim 11 , wherein the crystalline oxide layer is an aluminum oxide compound. 
     
     
         20 . The device of  claim 19 , wherein the aluminum oxide compound is lanthanum aluminum (LaAI03).