Growth of (001) preferentially oriented BiFeO3 films on Si substrate by sol-gel method

Obtaining high-quality oriented/textured BFO thin films on traditional Si substrates by low-cost manageable sol-gel method is still challenging and currently relevant. The paper presents a comprehensive set of experimental investigations on the role of the buffer-layer (None, Pt/Ti/SiO2, and LNO) and the thickness of LNO&BFO films on the crystalline structure and microstructure involution of sol-gel based spin-coated BFO films on Si substrates. All BFO and LNO films exhibit good crystallinity and pure perovskite phase. No obvious preferential orientation was found in BFO films fabricated on bare Si(100) and Pt(111)/Ti/SiO2/Si substrates. While highly (001) preferred orientation was obtained for BFO film spin-coated on LNO(00l)/Si substrate. It demonstrated that highly oriented LNO buffer-layer with a certain thickness can promise the growth of high quality oriented/textured BFO thin films. In addition, the crystallization, orientation, phase, grain size, strain state and dislocation are all dependent on the film thickness. The XRD, SEM and W-Hequation theoretical analysis results illuminate that the thickness of the BFO films may affect the stress relaxation state, and then the grain size, dislocation and orientation. We demonstrate that suitable buffer-layer materials, optimized thickness of buffer-layer and ferroelectric film have relevant role on the development of high-quality oriented BFO thin films on Si prepared by sol-gel and derived silicon based devices.