A Comprehensive Study on the Frequency-Dependent Electrical Characteristics of Sm2O3 MOS Capacitors

In this paper, we report comprehensive frequency-dependent electrical characterizations of samarium oxide (Sm₂O₃) MOS capacitors. The Sm₂O₃ crystal structure and phase identifications of the films were confirmed by X-ray diffractometry. The electrical characterizations were performed in the wide frequency ranges by the capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements at room temperature and series resistance effects were investigated following the correction of the measured C-V and G/ω-V characteristics. Significant changes have been observed in capacitance, especially in conductance curves following the corrections. Interestingly, the corrected conductance gives two distinct peaks in the corresponding depletion and inversion edge. The Gc/ω-V characteristics in the low-frequency regions decrease with increasing in the frequency, in the high-frequency regions slightly increase with increasing infrequency. In addition, similar distinct behaviors have been observed for the calculated interface state density, diffusion, and barrier potential at low-high frequencies. The main reason of these behaviors can be attributed to the acceptor-/donor-like interface states and/or different relaxation time dependences of interface states. These results demonstrate that series resistance and interface states should be considered during the electrical characterization. Calculated interface density and barrier potential are suitable to use the Sm₂O₃ as a dielectric layer for MOS-based applications.