Growth and characterization of AlGaN/GaN HEMT on SiCOI substrates

AlGaN/GaN high electron mobility transistors (HEMT) were grown by metal-organic chemical vapor deposition (MOCVD) on SiCOI substrates. These substrates consist of SiC/SiO2/Si (SiCOI) manufactured by the Smart CutTM technology, and currently enable up to 3 µm of GaN to be grown crack-free. The structures were investigated by low-temperature (LT) photoluminescence (PL) measurements (full width of half maximum (FWHM) = 5 meV). Unpassivated transistors with a gate length of 1.4 µm and a gate width of 2 × 50 µm exhibit a maximum drain current density of 540 mA/mm at VGS = 1 V and VDS = 4.5 V in stationary mode with an extrinsic transconductance (gm) of 130 mS/mm. The cut-off frequency and maximum frequency of oscillation were 6.7 and 11.6 GHz, respectively. Additionally, these devices allow a high operating voltage VDS which is demonstrated in maximum breakdown voltages higher than 100 V. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)