Zirconium and hafnium boride alloy templates on silicon for nitride integration applications
First Claim
1. A method for forming an epitaxial buffer layer over a substrate by molecular beam epitaxy comprising:
- contacting a substrate with a precursor gas at a temperature and a pressure suitable for depositing an epitaxial buffer layer over the substrate;
the epitaxial buffer layer having a thickness of greater than 100 nm and comprising ZrB2, AlB2, HfB2, HfxZr1-xB2, HfxAl1-xB2, ZrxAl1-xB2, or ZrzHfyAl1-z-yB2 wherein the sum of z and y is less than or equal to 1;
wherein the precursor gas comprises (i) greater than 95% v/v hydrogen gas and (ii) 0.1-5% v/v of a precursor source, wherein the precursor source comprises Zr(BH4)4, Hf(BH4)4, an Al source, or mixtures thereof; and
wherein the use of the hydrogen gas reduces the surface roughness of the epitaxial layer by acting as a diluent to prevent the poisoning of the surface of the epitaxial layer with B-rich fragments.
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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.
13 Citations
18 Claims
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1. A method for forming an epitaxial buffer layer over a substrate by molecular beam epitaxy comprising:
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contacting a substrate with a precursor gas at a temperature and a pressure suitable for depositing an epitaxial buffer layer over the substrate; the epitaxial buffer layer having a thickness of greater than 100 nm and comprising ZrB2, AlB2, HfB2, HfxZr1-xB2, HfxAl1-xB2, ZrxAl1-xB2, or ZrzHfyAl1-z-yB2 wherein the sum of z and y is less than or equal to 1; wherein the precursor gas comprises (i) greater than 95% v/v hydrogen gas and (ii) 0.1-5% v/v of a precursor source, wherein the precursor source comprises Zr(BH4)4, Hf(BH4)4, an Al source, or mixtures thereof; and wherein the use of the hydrogen gas reduces the surface roughness of the epitaxial layer by acting as a diluent to prevent the poisoning of the surface of the epitaxial layer with B-rich fragments. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification