High-crystal-quality Al0.26Ga0.74N/AlN/GaN structures with a very high mobility, such as over 2100cm2/(V s) with a two-dimensional-electron gas (2DEG) density of approximately 1 × 10 13/cm2, were grown on epitaxial AIN/sapphire templates by metalorganic vapor phase epitaxy and adopted for the fabrication of high-electron-mobility transistors (HEMTs). The fabricated devices showed good DC characteristics compared with those in conventional AlGaN/GaN HEMTs and in devices grown on sapphire substrates. Also, it was confirmed that further improvements in DC characteristics are achieved by applying recessed ohmic contacts to AlGaN/AlN/GaN HEMTs. A high extrinsic transconductance of approximately 220mS/mm and a high drain current density of over 1 A/mm with a threshold voltage of -4.08 V were obtained for 1,5-μm-gate-length recessed ohmic AlGaN/AlN/GaN HEMTs on AIN/sapphire templates. In addition, it was found that the gate leakage current of HEMTs can be suppressed by using epitaxial AIN/sapphire templates as substrates.
|ジャーナル||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|出版ステータス||Published - 2005 9 8|
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