Investigation of band alignment between InAIAs and atomic-layer-deposited HfO_2/AI_2O_3 by X-ray photoelectron spectroscopy

摘要

Band alignments between atomic layer deposition (ALD) HfO2/Al2O3 double layers and InAlAs were investigated by angle-resolved X-ray photoelectron spectroscopy (AR-XPS). The relationship of As and Hf 4f peaks reducing with the decreasing take-off angle theta indicated upward band bending on the InAlAs surface and a potential gradient in the HfO2/Al2O3 layer. AR-XPS measurements were combined with numerical calculations. The valence band and conduction band discontinuity between HfO2/Al2O3 and InAlAs were 2.49 +/- 0.2 eV and 1.86 +/- 0.2 eV, respectively. A low leakage current density of 7.01 x 10(-7) A cm(-2) at 1 V and oxide trapped charge densities of 9.925 x 10(11) cm-(2 )were obtained. (C) 2019 The Japan Society of Applied Physics