Investigation of structural properties, electrical and dielectrical characteristics of Al/Dy2O3/porous Si heterostructure

• The high-k Dy2O3 oxide film is deposited on the porous Si by means of electron beam deposition.
• Structural properties of Al/Dy2O3/porous Si heterostructure are investigated.
• The electrical properties of Al/Dy2O3/porous Si heterostructure are studied.
• The I (V) characteristic shows a low leakage current.

This paper describes the structural properties, electrical and dielectric characteristics for the first time of the high-k Dy2O3 oxide film deposited on the porous Si substrate by electron beam deposition under ultra vacuum. Structural and morphological characterizations are investigated by a scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray diffraction measurements (XRD). The electrical and dielectric characteristics of the Al/Dy2O3/porous Si heterostructure are studied through current- voltage I (V), capacitance–voltage C (V), conductance- and capacitance-frequency dependencies (G (f) and C (f)). Therefore, the dominant conduction mechanisms for the Al/Dy2O3/porous Si heterostructure are extracted from the determining of Schottky coefficient (βSC) and Poole–Frenkel coefficient (βPF). The experimental values of βSC and βPF coefficients are calculated from I (V) characteristics and compared with theoretical values, thus, the appropriate model has been proposed. The C (V) characteristics at different frequencies revealed a large frequency-dispersion, indicative of a significant density of interface states. Furthermore, the G (f) characteristics were well fitted by the modified law GAC(f)=A1fs1+A2fs2(f)=A1fs1+A2fs2 and the results showed frequency dependent and evidence of two different behaviors in ac conductance i.e. the low-frequency conductivity is due to long-range ordering (frequency-independent) and high frequency conduction due to the localized orientation hopping mechanism. The Nyquist diagrams are used to identify the equivalent circuit, so, the Al/Dy2O3/porous Si heterostructure is accurately modeled at frequency ranges from 10 Hz to 1000 kHz, as a two parallel elements (RC) network placed in series.