The temperature dependence on the electrical properties of dysprosium oxide deposited on n-porous GaAs

This paper describes the electrical and dielectric characteristics for the first time of the high-k Dy2O3 oxide film deposited on the porous GaAs substrate by electron beam deposition under ultra vacuum. Morphological characterization is investigated by atomic force microscopy (AFM). The electrical and dielectric properties of Co/Au/Dy2O3/n-porous GaAs structure were studied in the temperature range of 80-500 K. The conductance and capacitance measurements were performed as a function of bias voltage and frequency. The dielectric constant (ε′), dielectric loss (ε″) and dielectric loss tangent (tanδ) of the structure are obtained from capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements. These parameters are found to be strong functions of temperature and bias voltage. In the forward bias region, C-V plots show a negative capacitance (NC) behavior, ε′-V plots for each temperature value take negative values as well. Such negative values of C correspond to the maximum of the conductance (G/ω). The negative capacitance values appear abnormal when compared to the conventional behavior of ideal Schottky barrier diode (SBD) and metal-oxide-semiconductor (MOS) structures. The following behavior of the C and ε′ in the forward bias region has been explained with the minority-carrier injection and relaxation theory. From DC conductance study, electronic conduction is found to be dominated by thermally activated hopping at high temperature. Activation energy is deduced from the variation of conductance with temperature. The Nyquist plots exhibited single semi-circular arcs which were well fitted to an equivalent circuit.