SBIR Phase II: Sonic Lift-Off (SLO) for Lower Cost Wide Bandgap Devices

The broader/commercial impact of this Small Business Innovation Research (SBIR) Phase II project will be to accelerate the adoption of next generation semiconductor power devices based on Gallium Nitride. Gallium Nitride (GaN) devices, compared to legacy Silicon devices, offer much increased performance and energy efficiency across a wide range of applications, including those essential for the Nation’s future energy, transportation and communications infrastructure. The project is impacting the adoption of GaN devices by significantly lowering the production costs. It is estimated that replacing power conversion devices based on Silicon with GaN (and SiC, another advanced material) will be able to save 120 TWh/year, corresponding to the energy consumption of a whole country like Switzerland. In addition to energy savings, GaN devices will furthermore allow further miniaturization of power supplies, car chargers, and other everyday consumer and industrial appliances. The ability to re-use GaN wafers during the manufacturing process in addition lowers energy consumption and pollution in the manufacturing process of these devices. This Small Business Innovation Research (SBIR) Phase II project will develop a process that allows multiple re-use of GaN wafers for advanced power electronics. GaN wafer costs are very high and dominate the cost of power devices manufactured from it. The objective is to develop a process that uses sound energy in combination with stressing the wafer material to precisely cut the semiconductor material and release a thin layer from the surface of a GaN wafer leaving the wafer for subsequent reuse, possibly multiple times. This cuts the material cost per device manufactured significantly. The development of this process involves optimization of the materials used to generate the stress in the wafer, the acoustic energy delivery system, and determination of ideal process parameters. The desired outcome of the project is the demonstration of a reproducible process to lift-off thin (on the order of twenty micrometers) layers of GaN from a thick (500 micrometers) semiconductor wafer leaving a low roughness, damage-free surface for processing the next device layer. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.