Relaxed InGaN/AlGaN templates

US8143154B2 · kind B2 · utility

Assignee

• Palo Alto Research Center Incorporated · US

Inventors

• Christopher L. Chua · San Jose, US
• Zhihong Yang · San Jose, US
• Andre Strittmatter · Magdeburg, DE
• Mark R. Teepe · Menlo Park, US

Key dates

• Filing date: Jul 28, 2011
• Grant date: Mar 27, 2012
• Expiry date: Jul 28, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10H20/825
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

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.