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BGaN Micro-Islands as Novel Buffers for GaN Hetero-Epitaxy

2005; Institute of Physics; Volume: 44; Issue: 12L Linguagem: Inglês

10.1143/jjap.44.l1506

1347-4065

Tetsuya Akasaka, Toshiki Makimōto,

Ga2O3 and related materials

B x Ga 1- x N ( x ∼0.02) micro-islands provide novel buffers for growing GaN films and AlGaN/GaN heterostructures on sapphire substrates. These films and heterostructures show low threading dislocation density (TDD), low residual carrier concentration, and high two-dimensional electron gas (2DEG) mobility: Non-doped GaN films had the TDD of 2×10 8 cm -2 and the residual electron concentration of 9.4×10 9 cm -3 at 433 K. AlGaN/GaN heterostructures exhibited 2DEG Hall mobility of 1720 and 13100 cm 2 V -1 s -1 at 300 and 77 K, respectively. An almost constant sheet electron density (2.9–4.2×10 12 cm -2 ) was obtained in the wide temperature range from 500 to 77 K, indicating the absence of parallel conduction in the GaN buffer layers.