Energy band alignment of HfO2 on p-type（100）InP

The band alignment of HfO2 film on p-type（100） InP substrate grown by magnetron sputtering was investigated.The chemical states and bonding characteristics of the system were characterized by X-ray photoelectron spectroscopy（XPS）.The results show that there is no existence of Hf-P or Hf-In and there are interfacial In2O3and InPO4 at the interface.Ultraviolet spectrophotometer（UVS） was employed to obtain the band gap value of HfO2.In 3d and Hf 4f core-level spectra and valence spectra were employed to obtain the valence band offset of HfO2/InP.Experimental results show that the（5.88 ± 0.05） eV band gap of HfO2 is aligned to the band gap of InP with a conduction band offset（ΔEc） of（2.74 ± 0.05） eV and a valence band offset（ΔEv） of（1.80 ± 0.05） eV.Compared with HfO2 on Si,HfO2 on InP exhibits a much larger conduction band offset（1.35 eV larger）,which is beneficial to suppress the tunneling leakage current.