Band alignment of HfO2/multilayer MoS2 interface determined by x-ray photoelectron spectroscopy: Effect of CHF3 treatment

The energy band alignment between HfO2/multilayer (ML)-MoS2 was characterized using high-resolution x-ray photoelectron spectroscopy. The HfO2 was deposited using an atomic layer deposition tool, and ML-MoS2 was grown by chemical vapor deposition. A valence band offset (VBO) of 1.98 eV and a conduction band offset (CBO) of 2.72 eV were obtained for the HfO2/ML-MoS2 interface without any treatment. With CHF3 plasma treatment, a VBO and a CBO across the HfO2/ML-MoS2 interface were found to be 2.47 eV and 2.23 eV, respectively. The band alignment difference is believed to be dominated by the down-shift in the core level of Hf 4d and up-shift in the core level of Mo 3d, or the interface dipoles, which caused by the interfacial layer in rich of F.