Growth of AlGaN/GaN based electronic device structures with semi‐insulating GaN buffer and AlN interlayer

Heterostructures of GaN/AlGaN for power applications are grown by metal organic vapor phase epitaxy in a multiwafer reactor on sapphire and SiC substrates. The insulating properties of the GaN buffer and the influence of an AlN interlayer on the two-dimensional electron gas transport properties of high electron mobility transistor structures have been studied. By optimizing the growth conditions the resistivity could be increased to 1011 Ωcm. For GaN/AlGaN heterostructures on sapphire with a 1 nm AlN interlayer a room temperature mobility of 1780 cm2/Vs and an electron sheet carrier density of 1.2 ×1013 cm–2 were achieved. Power devices were fabricated on s.i. SiC showing a power density of 4.9 W/mm at 10 GHz for a multifinger transistor with a gate width of 1 mm. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)