Annealing effect and leakage current transport mechanisms of high k ternary GdAlOx gate dielectrics

Abstract In this work, ternary GdAlO x (GAO) thin films as new gate dielectric materials were offered by magnetron sputtering. The microstructure, band gap and electrical properties of ternary GAO gate dielectric thin films as functions of annealing temperatures were measured. It can be noted that annealing at 600 °C for 6 min in oxygen atmosphere is the best annealing process. And GAO thin films annealed at 500 °C–800 °C still express their amorphous state, showing excellent thermal stability. In addition, the films annealed at 600 °C have a maximum band gap of 5.36 eV. Electrical properties of all samples based on Pt/GAO/Si/Pt metal-oxide-semiconductor (MOS) capacitors have been investigated and they have been characterized by capacitance-voltage (C-V) and leakage current density-voltage (I-V) curves. Results show that the samples annealed at 600 °C display excellent performance such as highest dielectric constant ( k ) of 21.2 and lowest current density of 4.94  ×  10 −3 A/cm 2 at V fb -1 V. Therefore, the GAO thin films annealed at 600 °C can be used as one of candidate high- k gate dielectric materials in future. Finally, the leakage current transport mechanisms of all Pt/GAO/Si/Pt MOS capacitors have been discussed in detail.