Epitaxial GaN on flexible metal tapes for low-cost transistor devices

GaN-based devices are the basis of a variety of modern electronics applications, especially in optoelectronics and high-frequency / high-power electronics. These devices are based on epitaxial films grown on single-crystal wafers. The single-crystal wafer substrates are limiting because of their size, expense, mechanical properties and availability. If one could make GaN-based devices over large areas and on a wide variety of substrates including flexible inexpensive foils, and thereby monolithically integrate devices on these technical substrates, one could broaden the applicability of these devices, enable new functionalities and products, and significantly reduce their cost. Our company, a spin off from Los Alamos National Laboratory (LANL), is using a technology known as ion-beam assisted deposition (IBAD) texturing, developed extensively at LANL, that allows thin films to be grown on arbitrary substrates with crystalline biaxial alignment. This technology has been successfully used in superconductor wire manufacturing where grain alignment is critically important in order for the wires to carry high currents. We propose to apply our experience with this technology and work with Sandia National Laboratories to apply IBAD texturing to epitaxial GaN films and thereby explore a variety of technical substrates, incl. metal foils and glass. These films will then be used to demonstrate high-power transistor devices. The research proposed in this SBIR, if carried out, will provide a novel approach to fabrication of GaN devices. By using metal tapes and foils as substrates this fabrication method should lead to a revolution in GaN devices. The breakthrough in the proposed approach will provide a scalable technology for fabrication of low-cost GaN transistor devices.