AlGaN/GaN heterostructure field-effect transistors regrown on nitrogen implanted templates

We demonstrate the application of nitrogen (N) implantation in GaN as a current-blocking layer. In a first step, vertical current-blocking behavior was confirmed by processing quasi-vertical Schottky diodes with full-area N-implantation. The leakage current was only 10−6 A cm−2 in forward and reverse directions. Also, the regrowth of AlGaN/GaN heterostructure field-effect transistors on N-implanted and, for reference, non-implanted GaN templates is demonstrated. Even though a decrease in the mobility and sheet carrier density of the two-dimensional electron gas was observed, excellent off-state properties were achieved. Regrown devices exhibited leakage currents as low as 10−7 mA mm−1, showing very good quality of the regrowth interface. However, a detailed analysis with pulsed I–V and C–V measurements suggest an increased presence of traps due to regrowth, especially on N-implanted templates.