Energy band alignment of HfO2 on p-type (100)InP
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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 In2O3 and 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 (∆E c) of (2.74 ± 0.05) eV and a valence band offset (∆E v) 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.
KeywordsBand alignment HfO2 InP Large conduction band offset
This study was financially supported by the National Natural Science Foundation of China (Nos. 50932001, 51102020, and 51202013).
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