Characterization of ALCVD-Al2O3 and ZrO2 layer using X-ray photoelectron spectroscopy

The atomic layer chemical vapor deposition (ALCVD) deposited Al₂O₃ and ZrO₂ films were investigated by ex situ X-ray photoelectron spectroscopy. The thickness dependence of band gap and valence band alignment was determined for these two dielectric layers. For layers thicker than 0.9 nm (Al₂O₃) or 0.6 nm (ZrO₂), the band gaps of the Al₂O₃ and ZrO₂ films deposited by ALCVD are 6.7±0.2 and 5.6±0.2 eV, respectively. The valence band offsets at the Al₂O₃/Si and ZrO₂/Si interface are determined to be 2.9±0.2 and 2.5±0.2 eV, respectively. Finally, the escape depths of Al 2p in Al₂O₃ and Zr 3p3 in ZrO₂ are 2.7 and 2.0 nm, respectively.