Electrical and transport properties of europium-indium oxide films prepared on Si(1 0 0) substrates

Abstract

Thin EU–In binary oxide films were prepared by alternating deposition method on Si (P) substrates to form metal–oxide–Si(MOS) devices. These films were annealed at different conditions and characterised by X-ray fluorescence (EDXRF) and X-ray diffraction (XRD). The capacitance–gate voltage ( C– V g) dependence was used to investigate the effect of annealing conditions on the trapped-fixed charge concentration in the oxide and on the relative permittivity of the film sample. It was observed that the prepared crystalline-dielectric Solid Solution (SS) of EU–In oxide has a sufficiently high relative permittivity ε , around 30. This suggests that it is a promising candidate for high- ε dielectric applications. The DC electrical properties of EU–In binary oxides insulator were investigated. The current–voltage J( V g) and current–temperature J( T) characteristics refer to different current transfer processes depending on the annealing conditions, i.e., on the structure and trap concentration. The current transfer in the oxide film sample with mixed amorphous Eu oxide and polycrystalline In 2O 3 is governed by Poole–Frenkel (PF) mechanism of barrier height 0.15 eV while in the oxide film with mixed polycrystallines Eu 2O 3 and In 2O 3 follows the trap-charge-limited space-charge-limited conductivity (TCLC–SCLC) mechanism characterised by exponential distribution of traps of temperature parameter of 512.8 K and total trap concentration ( N t) of 4.2×10 22 m −3. The current transfer in MOS device with dielectric solid solution of EU–In oxide follows the TCLC–SCLC mechanism with temperature parameter of 427.8 K and N t of 2.2×10 23 m −3. It was concluded that the carrier traps in those crystalline films are distributed exponentially in energy within the band gap. These concentrations N t were compared with the concentrations of the fixed charges in the films calculated from the capacitance measurements, which was around 10 22 charges/m 3.