Novel Process for Low-cost Large-area GaN Templates on Metal Foils

Wide band gap devices are considered a key future electronics technology in a number of applications especially for high-power electronics. These devices are based on high-quality epitaxial films of wide band gap materials such as GaN deposited on single-crystal wafers. The single-crystal substrates are limiting because of the wafer size, expense, mechanical properties and availability. Providing the industry with flexible device-quality GaN templates in large areas will enable very low-cost GaN power devices. iBeam Materials has very recently demonstrated the first ever device quality epitaxial GaN films on metal foils using ion beam assisted deposition (IBAD) textured templates. By combining textured thin films with extremely high-rate epitaxial semiconductor deposition by hydride vapor phase epitaxy (HVPE), this proposal seeks to enable low-cost epitaxial GaN templates for power electronics and printed electronics. Currently, epitaxial GaN is deposited on rigid, single-crystal wafers such as sapphire, silicon carbide (SiC) and silicon. Substrates with physical properties matched to GaN can be costly (notably SiC), while lower cost substrates such as silicon have poor coefficient of thermal expansion (CTE) match to GaN. iBeam Materials is able to provide an alternative substrate which is low-cost, CTE-matched to GaN, and flexible. This is done by employing ion-beam assisted deposition (IBAD) technology to make single-crystal like coatings on substrates such as metal foils. iBeam has recently demonstrated epi-GaN by metal organic chemical vapor deposition (MOCVD) on metal substrates and the first-in-the-world LED fabricated on a metal foil. By combining IBAD texturing thin film technology on flexible long-length metal substrates with a low-cost, high- throughput HVPE GaN process, this project aims to develop a truly low-cost epitaxial GaN template for the wide-bandgap device community. This technology will provide device designers and researchers with a completely new platform for development of MOCVD GaN devices and enable new devices such as printed LEDs, flexible displays or integrated power electronics. Commercial Applications and Other Benefits: The research proposed in this Phase I, if carried out, will provide a novel approach to fabrication of GaN templates for a variety of devices. By using metal tapes and foils as substrates this fabrication method may lead to a revolution in GaN devices. The breakthrough in the proposed approach will provide a scalable technology for fabrication of GaN templates for large area GaN power devices as well as LED’s on large-area, flexible substrates.