Zirconium and hafnium boride alloy templates on silicon for nitride integration applications

• US 8,803,194 B2
• Filed: 01/04/2008
• Issued: 08/12/2014
• Est. Priority Date: 01/04/2007
• Status: Active Grant

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Kouvetakis, John, Roucka, Radek
• Primary Examiner(s): Nguyen, Ha Tran T
• Assistant Examiner(s): Gupta, Raj R
• Application Number:
  US11/969,689
• Publication Number:
  US 20080164570A1
• Time in Patent Office: 2,412 Days
• Field of Search: 117/108, 257/190, 257/E29.193, 257E21123-125
• US Class Current: 257/190
• CPC Class Codes: C30B 25/183 being provided with a buffer layer, e.g. a lattice matching layer
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 33/007 comprising nitride compounds

Abstract

Semiconductor structures are provided comprising a substrate and a epitaxial layer formed over the substrate, wherein the epitaxial layer comprises B; and one or more element selected from the group consisting of Zr, Hf and Al and has a thickness greater than 50 nm. Further, methods for integrating Group III nitrides onto a substrate comprising, forming an epitaxial buffer layer of a diboride of Zr, Hf, Al, or mixtures thereof, over a substrate; and forming a Group III nitride layer over the buffer layer, are provided which serve to thermally decouple the buffer layer from the underlying substrate, thereby greatly reducing the strain induced in the semiconductor structures upon fabrication and/or operation.

Claims

1. A semiconductor structure comprising a substrate and an epitaxial layer formed over the substrate, wherein the epitaxial layer comprises B and one or more elements selected from the group consisting of Zr, Hf and Al;

and the epitaxial layer has a thickness greater than 200 nm; and

the epitaxial layer is thermally decoupled from the substrate.

2. The semiconductor structure of claim 1, wherein the epitaxial layer has one or more properties selected from the group consisting of,

(i) relaxed at 900°

C.;

(ii) a mismatch strain which is essentially thermally constant over a temperature range of room temperature to 900°

C.; and

(iii) an atomically flat surface.

3. The semiconductor structure of claim 1 wherein the epitaxial layer comprises ZrB₂, AlB₂, or HfB₂.

4. The semiconductor structure of claim 1, wherein the epitaxial layer is formed by molecular beam epitaxy or chemical vapor deposition.

5. The semiconductor structure of claim 1, further comprising an active layer formed over the epitaxial layer.

6. The semiconductor structure of claim 5, wherein the active layer has one or more properties selected from the group consisting of

(i) lattice-matched to the epitaxial film;

(ii) comprising a Group III nitride; and

(iii) comprising a compound which is selected from the group consisting of GaN, AlGaN, InGaN, AlInGaN, AlN, InN, and SiCAlN, or mixtures thereof.

7. The semiconductor structure of claim 1, wherein the substrate comprises Si, Al₂O₃, SiC or GaAs.

8. The semiconductor structure of claim 7 wherein the substrate comprises Si (100) or Si(111).

9. The semiconductor structure of claim 7 wherein the substrate comprises a miscut Si(111) substrate.

10. The semiconductor structure of claim 1, wherein the epitaxial layer is formed directly on the substrate, and comprises B and two or more elements selected from the group consisting of Zr, Hf and Al.

11. The semiconductor structure of claim 10, further comprising an epitaxial HfB₂ layer formed directly on the epitaxial layer.

12. The semiconductor structure of claim 1, wherein the epitaxial layer is formed directly on the substrate and comprises ZrB₂.

13. The semiconductor structure of claim 12, further comprising an epitaxial HfB₂ layer formed directly on the epitaxial layer.