Develop Ultra-Fast Metastable Ion Implant Activation System

Gallium Nitride (GaN) has numerous fundamental figures of merit which provide advantages over SiC and Si, which are, respectively, the current state-of-the-art and standard material systems for power devices. With the Baliga figure of merit, respectively, ~ 5× and ~850× higher than SiC and Si, GaN-based technology will enable >10kV power switching devices. Yet, establishing complex device geometries and doping profiles required for the manufacturing of efficient high-voltage and high-frequency devices remained to be the major hurdle in the field. To realize this, reliable ion implantation followed by post-implantation damage removal and electrical activation by annealing would be critical for the selective area doping. However, unlike SiC and Si material systems, GaN is thermodynamically unstable at high temperatures, prohibiting the use of conventional annealing methods such as Rapid Thermal Annealing (RTA) to anneal structural damage from GaN devices. Annealing to satisfactorily reduce implant-induced damage typically requires temperatures ~2/3, the melting point of the crystal, which is ~1400-1500 °C for GaN. But GaN surface decomposes only at a temperature of ~850 °C at atmospheric pressure.  In this project, we propose to develop a multicycle rapid thermal annealing (MRTA) system with ultrafast sub-second heating and cooling cycle rates (>1000 K/s) that allows shorter temperature pulses (but multiple times) and thereby achieve higher maximum peak temperature in GaN without decomposing the material. The short cycled multiple heating pulses provide better conditions for diffusional processes in GaN, results in better restoration of the device structure damaged by ion implantation, and improves activation of the implanted dopants while also preserving the integrity of the GaN surface.