Electrical and Dielectric Properties of a Dy2O3 MOS Capacitor

A dysprosium oxide (Dy 2 O 3 ) gate dielectric layer was deposited by electron beam deposition under ultra-vacuum onto p-GaAs (100) substrate. Morphological characterization was determined based on atomic force microscopy images. The x-ray diffraction results indicate that the Dy 2 O 3 oxide is polycrystalline. The interface properties of the (Au/Co)/Dy 2 O 3 /p-GaAs metal oxide semiconductor (MOS) capacitor was investigated by measuring the capacitance–voltage (C–V) and conductance–voltage (G/w–V) in the temperature and frequency ranges 80-500 K and 50 Hz to 1 MHz, respectively. Both the capacitance and conductance of the MOS capacitor are frequency- and temperature-dependent. The interface state density (Nss-V) distribution profile obtained from high-frequency–low-frequency (CHF–CLF) capacitance measurement indicates a peak in the depletion zone. In addition, the interface state density (Nss) value determined by the Hill-Coleman method of the (Au/Co)/Dy 2 O 3 /p-GaAs (MOS) capacitor was decreased with increasing temperature. The obtained results show that the interface states are important parameters that strongly influence the electric parameters of the studied MOS capacitor. The alternating current conductivity is strongly dependent on the applied frequency, voltage and temperature. The conductance against reciprocal temperature plots reveal a sequence of two activation energies of 20 meV and 86 meV at low and high temperature, respectively. Schottky emission and Fowler-Nordheim tunneling are the conduction mechanisms in the oxide layer, according to an investigation of leakage current characteristics.