Impact of AlN Interfacial Dipole on Effective Work Function of Ni and Band Alignment of Ni/HfO2/In0.53Ga0.47As Gate-Stack

AlN has successfully been applied to passivate the oxide/III-V interface; however, it changes both the metal work function (WF) and band alignment of the gate-stack and, thus, affects the power consumption of the devices. We found that the AlN layer induces a dipole δ = 0.18 eV between HfO₂ and substrate. The dipole value obtained from capacitance- voltage characteristics performs good agreement with the results of X-ray photoelectron spectroscopic measurements. The effective WF of Ni is found to be 5.55 eV, which is larger than its WF in vacuum. The valance band offset and the conduction band offset of HfO₂ with AlN/In_0.53Ga_0.47As are found to be 2.82 and 2.06 eV, respectively.