Effect of oxidation temperature on physical and electrical properties of ZrO2 thin-film gate oxide on Ge substrate

Publication date: Available online 5 October 2017
Source:Thin Solid Films
Author(s): Zhen Ce Lei, Kian Heng Goh, Nor Ishida Zainal Abidin, Yew Hoong Wong
The effects of oxidation temperatures on metal-oxide-semiconductor characteristics of sputtered zirconium thin films on germanium systematically investigated in an oxygen ambient. The samples were oxidized for 15min at temperatures varying between 300°C and 800°C. The sample oxidized at 500°C has demonstrated the highest electrical breakdown field of 16.6MVcm⁻¹. The crystallinity of the film was evaluated by X-ray diffraction, Fourier-transform infrared, Raman, and X-ray photoelectron spectroscopy analyses were also performed. The crystallite size and microstrain of the films were estimated by Williamson-Hall plot analysis. Optical microscopy was used to examine the sample surfaces and high-resolution transmission electron microscopy was carried out to investigate the cross-sectional structure. GeO2 was detected in samples oxidized at temperature above 600°C. A possible thermal oxidation mechanism related to the diffusion of oxygen through the ZrO2 layer and formation of germanium dioxide has been proposed and discussed.