Effect of annealing temperature on the electrical characteristics of Al/Er2O3/n-Si/Al MOS capacitors

In this work, Er2O3 films deposited by electron beam (E-beam) evaporation technique were annealed at 450 degrees C, 550 degrees C, and 650 degrees C in N-2 atmosphere for 30 min. We then compared the electrical properties, the frequency dependency of the density of interface states, and series resistance of as-deposited and annealed Al/Er2O3/n-Si/Al MOS capacitors. The grain size measurements carried out by X-ray diffractometer (XRD) and the root mean square (RMS) surface roughness values obtained by atomic force microscopy (AFM) increased with an increase of annealing temperature. The C-V and G/omega-V measurements were carried out at a frequency of 1 MHz for as-deposited and annealed MOS capacitors. The capacitance in the accumulation region decreased with an increase in annealing temperature, and the capacitor film annealed at 450 degrees C had the highest capacitance in the accumulation region as well as high-k value, and low barrier height. In addition, the C-V and G/omega-V measurements carried out in the frequency range of 20 kHz to 1 MHz were analyzed to understand the effect of frequency on the series resistance (R-s) and interface states (D-it). The measured and calculated results reveal a significant influence of frequency on both R-s and D-it of the fabricated MOS capacitor characteristics. (C) 2021 Elsevier B.V. All rights reserved.