Multiwafer epitaxy of GaN/AlGaN heterostructures for power applications

Heterostructures of GaN/AlGaN for power applications are grown by metal organic vapor phase epitaxy in a multiwafer reactor on sapphire and SiC substrates. Electrical properties of the two-dimensional electron gas are discussed. The sheet carrier concentration was varied from 4x1012 cm-2 to 1.5x1013 cm-2 by modulation doping. From electrical and material properties we show the excellent uniformity of the wafers. The influence of the Al content on the sheet carrier concentration is demonstrated. A maximum electron mobility of 1500 cm2/Vs is achieved for an undoped sample. Device fabrication was done on full 2" wafers b electron-beam and contact lithography. The quality of the grown epi layers and the technology is confirmed by CW load pull measurements at 2 GHz and 10 GHz.