Shallow trench isolation regions made from crystalline oxides
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.
1. A method of forming a semiconductor structure comprising:
providing a semiconductor substrate;
forming a nitride layer on said substrate;
etching a trench into said semiconductor substrate, wherein said trench is formed in said nitride layer and said substrate;
forming an epitaxial oxide structure by growing a crystalline oxide layer in a portion of said trench located below a bottommost surface of said nitride layer, wherein the crystalline oxide layer fills an entire volume of the trench located below a topmost planar surface of said substrate;
removing said nitride layer; 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.
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 ) or an aluminum oxide compound.
9. The method of claim 1 , wherein said crystalline oxide layer is formed selectively on said semiconductor surface.
10. The method of claim 9 , wherein said crystalline oxide layer is not formed on said nitride layer.