Structural and nanomechanical properties of BiFeO3 thin films deposited by radio frequency magnetron sputtering
1 Department of Materials Science and Engineering, I-Shou University, Kaohsiung 840, Taiwan
2 Department of Applied Physics, Tunghai University, Taichung 407, Taiwan
3 Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan
Nanoscale Research Letters 2013, 8:297 doi:10.1186/1556-276X-8-297Published: 25 June 2013
The nanomechanical properties of BiFeO3 (BFO) thin films are subjected to nanoindentation evaluation. BFO thin films are grown on the Pt/Ti/SiO2/Si substrates by using radio frequency magnetron sputtering with various deposition temperatures. The structure was analyzed by X-ray diffraction, and the results confirmed the presence of BFO phases. Atomic force microscopy revealed that the average film surface roughness increased with increasing of the deposition temperature. A Berkovich nanoindenter operated with the continuous contact stiffness measurement option indicated that the hardness decreases from 10.6 to 6.8 GPa for films deposited at 350°C and 450°C, respectively. In contrast, Young's modulus for the former is 170.8 GPa as compared to a value of 131.4 GPa for the latter. The relationship between the hardness and film grain size appears to follow closely with the Hall–Petch equation.