This letter investigates anomalous traps measured by charge pumping technique in high voltage in HfO2/metal gate n-channel metal-oxide-semiconductor field-effect transistors. N-Vhigh level characteristic curves with different duty ratios indicate that the electron discharge time dominates the value of N for extra traps. By fitting ln (N (tbase level = 2.5μs)-N (tbase level))-Δtbase level at different temperatures and computing the equation t = τ0 exp (αe,SiO2d SiO2 + αe,HfO2d HfO2,trap), results show that these extra traps measured by the charge pumping technique at high voltage can be attributed to high-k bulk shallow traps. [ABSTRACT FROM AUTHOR]