Very high channel conductivity in low-defect AlN/GaN high electron mobility transistor structures

摘要

Low defect AlN/GaN high electron mobility transistor (HEMT) structures, with very high values of electron mobility (＞ 1800 cm~2/V s) and sheet charge density (＞3 × 10~(13) cm~(-2)), were grown by rf plasma-assisted molecular beam epitaxy (MBE) on sapphire and SiC, resulting in sheet resistivity values down to ～100 Ω/□ at room temperature. Fabricated 1.2 μm gate devices showed excellent current-voltage characteristics, including a zero gate saturation current density of ～ 1.3 A/mm and a peak transconductance of ～260 mS/mm. Here, an all MBE growth of optimized AlN/GaN HEMT structures plus the results of thin-film characterizations and device measurements are presented.