Defect capping for reduced defect density epitaxial articles

Abstract

An epitaxial article includes a substrate having a substrate surface having a substrate surface composition including crystalline defect or amorphous regions and crystalline non-defect regions. The crystalline defect or amorphous regions are recessed from the substrate surface by surface recess regions. A capping material fills the surface recess regions to provide capped defects that extend from a top of the defect regions to the substrate surface. The capping material is compositionally different from the substrate surface composition. An epitaxial layer over the substrate surface provides an average crystalline defect density in at least one area having a size ≧0.5 μm 2 that is ≧ two times lower than an average crystalline defect density in that area at or below the substrate surface.

1 . A method for forming an epitaxial layer on a substrate comprising a substrate surface having crystalline defect or amorphous regions and crystalline non-defect regions, comprising:
 preferential polishing or etching said crystalline defect or amorphous regions relative to said crystalline non-defect regions to form a decorated substrate surface comprising surface recess regions;   depositing a capping layer on said decorated substrate surface to cover said crystalline non-defect regions and to at least partially fill said surface recess regions;   patterning said capping layer by removing said capping layer over said crystalline non-defect regions to form exposed non-defect regions while retaining said capping layer in at least a portion of said surface recess regions, and   selective epitaxy to form said epitaxial layer, wherein said capping layer in said surface recess regions restricts epitaxial growth of said epitaxial layer over said surface recess regions.   
     
     
         2 . The method of  claim 1 , further comprising chemical mechanical polishing (CMP) after said selective epitaxy to a top surface of said epitaxial layer to provide atomic level smoothness. 
     
     
         3 . The method of  claim 1 , wherein said preferential polishing or etching comprises wet chemical etching. 
     
     
         4 . The method of  claim 1 , wherein said preferential polishing or etching comprises dry chemical etching. 
     
     
         5 . The method of  claim 1 , wherein said preferential polishing or etching comprises chemical mechanical polishing (CMP). 
     
     
         6 . The method of  claim 1 , further comprising chemical mechanical polishing (CMP) said decorated substrate surface to provide an atomic scale finish before said depositing. 
     
     
         7 . The method of  claim 1 , wherein said depositing comprises a blanket deposition, and said capping layer provides a masking function for restricting said epitaxial growth of said epitaxial layer over said surface recess regions. 
     
     
         8 . The method of  claim 7 , wherein said depositing comprises e physical, chemical or vapor deposition, or electrochemical or electroless deposition. 
     
     
         9 . The method of  claim 1 , wherein said patterning comprises chemical mechanical polishing (CMP). 
     
     
         10 . The method of  claim 1 , wherein said epitaxial layer is a homoepitaxial layer. 
     
     
         11 . The method of  claim 1  wherein said epitaxial layer is a heteroepitaxial layer. 
     
     
         12 . The method of  claim 1 , wherein said substrate comprises silicon having a 10 Angstrom to 1 mm thick first Group III-nitride semiconductor layer thereon and said epitaxial layer comprises a second Group III-nitride semiconductor layer. 
     
     
         13 . The method of  claim 1 , wherein said substrate comprises Si, SiC, SiGe, Si—Ge—C, diamond, GaN, AlN, sapphire, CdTe, GaAs, or Si with a epitaxial layer II-VI layer or an epitaxial Group III-nitride layer thereon. 
     
     
         14 . An epitaxial article, comprising:
 a substrate comprising a substrate surface having a substrate surface composition including crystalline defect or amorphous regions and crystalline non-defect regions, wherein said crystalline defect or amorphous regions are recessed from said substrate surface by surface recess regions;   a capping material filling said surface recess regions to provide capped defects that extend from a top of said crystalline defect or amorphous regions to said substrate surface, wherein said capping material is compositionally different from said substrate surface composition, and   an epitaxial layer over said substrate surface, wherein said epitaxial layer provides an average crystalline defect density in at least one area having a size ≧0.1 μm 2  that is ≧ two times lower than an average crystalline defect density in said area at or below said substrate surface.   
     
     
         15 . The epitaxial article of  claim 14 , wherein said epitaxial layer comprises a homo-epitaxial layer. 
     
     
         16 . The epitaxial article of  claim 14 , wherein said epitaxial layer comprises a hetero-epitaxial layer. 
     
     
         17 . The epitaxial article of  claim 14 , wherein said average crystalline defect density throughout said epitaxial layer is ≦10 8  cm −2 . 
     
     
         18 . The epitaxial article of  claim 14 , wherein said epitaxial layer comprises a group IV, II-VI, III-V material, or a binary ternary or quaternary alloy of said group II-VI material or said III-V material. 
     
     
         19 . The epitaxial article of  claim 14 , wherein a surface of said epitaxial layer has an atomic scale finish with a surface roughness less than 5 Å. 
     
     
         20 . The epitaxial article of  claim 14 , wherein said substrate comprises an epi substrate comprising silicon having a 10 A to 1 mm thick first Group III-nitride semiconductor layer thereon and said epitaxial layer comprises a second Group III-nitride semiconductor layer. 
     
     
         21 . The epitaxial article of  claim 20 , wherein said first and said second Group III-nitride semiconductor layers are independently selected from AlGaN, AlN, InN, and GaN. 
     
     
         22 . The epitaxial article of  claim 14 , wherein said substrate comprises SiC and said epitaxial layer comprises SiC. 
     
     
         23 . The epitaxial article of  claim 14 , wherein said substrate comprises SiGe, Si—Ge—C, SiC, GaAs, or CdTe, AlN, GaP, or sapphire.