Relaxed InGaN/AlGaN Templates

• Main Authors: STRITTMATTER ANDRE, TEEPE MARK R, CHUA CHRISTOPHER L, YANG ZHIHONG
• Format: Patent
• Language: English
• Published: 17.11.2011
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; BASIC ELECTRIC ELEMENTS; CHEMISTRY; CRYSTAL GROWTH; DEVICES USING STIMULATED EMISSION; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SEMICONDUCTOR DEVICES; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

A relaxed InGaN template is formed by growing a GaN or InGaN nucleation layer at low temperatures on a conventional base layer (e.g., sapphire). The nucleation layer is typically very rough and multi-crystalline. A single-crystal InGaN buffer layer is then grown at normal temperatures on the nucleation layer. Although not necessary, the buffer layer is typically undoped, and is usually grown at high pressures to encourage planarization and to improve surface smoothness. A subsequent n-doped cap layer can then be grown at low pressures to form the n-contact of a photonic or electronic device. In some cases, a wetting layer-typically low temperature AlN-is grown prior to the nucleation layer. Other templates, such as AlGaN on Si or SiC, are also produced using the method of the present invention.