Reproducible and uniform growth of GaN based HEMTs on 4 inch SiC by plasma assisted molecular beam epitaxy suitable for production

We report on the progress of plasma assisted molecular beam epitaxy (PA-MBE) of AlGaN/GaN based high-electronmobility-transistor (HEMT) structures towards a process suitable for production. A uniform growth process on SiC substrates with diameter up to 4 inch was developed with variations in thickness and composition of Delta d/d = 1% and Delta x = +0.5%, respectively, and an excellent run-to-run reproducibility. The device quality was evaluated after processing with a 4 inch technology. Processed wafers exhibit very good uniformity and yield. Identical performance of all transistors on the entire wafers with high power added efficiency (PAE) of 63%, power density of 6 W/mm, linear gain around 25 dB, and gate leakage currents below 10 mu A/mm at 2 GHz and 50 V drain bias were achieved. Accelerated lifetime tests revealed promising long term stability. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim