A method to increase sheet electron density and mobility by vacuum annealing for Ti/Al deposited AlGaN/GaN heterostructures

作者：Tokuda Hirokuni^*; Kojima Toshikazu; Kuzuhara Masaaki

来源：Applied Physics Letters, 2012, 101(8): 082111.

DOI：10.1063/1.4748169

Temperature dependence of sheet electron density (n(s)) and mobility (mu) for Ti/Al deposited AlGaN/GaN heterostructures annealed in vacuum has been investigated using Hall effect measurements. The vacuum annealing at 1020 K caused the increase in both n(s) and mu at room temperature, with the amount of one order of magnitude and 65%, respectively, as compared to without annealed sample. The amount of increase was much less for only Ti or Al deposited or totally thin Ti/Al deposited sample. The origin of the increase is attributed to tensile strain induced by vacuum annealing. The method is useful for reducing the ohmic contact resistivity and/or the access resistance between source and gate in AlGaN/GaN HEMTs.

• 出版日期2012-8-20