Trap Characterization of Atomic-Layer-Deposited Al-Incorporated HfO₂ Films on In_0.53Ga_0.47As

This study reports on the interface and border trap characterization of HfO2 films by incorporating Al2O3 via atomic-layer deposition (ALD) in several deposition ratios. Al incorporation lowers the dielectric constant (k) of the HfO2 film and reduces the frequency dispersion while providing a positive shift in the flat band voltage. X-ray photoelectron spectroscopy (XPS) analysis has validated the microstructural bonding formation, and a combination of XPS and reflected electron energy loss spectroscopy (REELS) was used to characterize the band structures of the films. The energy band gap (Eg) and barrier heights (Ec and Ev) showed an increase with increasing amount of Al in the deposited films. Al2O3 incorporation helps achieve better passivation than pure HfO2 and provides pinhole-free condensed film growth, which is justified as a reduction in trap density. The reduction of the traps and band gap enlargement helps to obtain a lower leakage current density.