Effects Of Post-annealed Treatment On Microstructures And Properties Of LaAlO₃ Thin Films

With the development of science and microelectronic technology, the feature size of MOSFET as the key device of integrated circuits is scaling down at a speed of Moore law. However, traditional SiO₂ gate dielectric materials fail to overcome the influence brought on by the quantum mechanical tunneling-effect, which is reduced by the scaling down of the MOSFET. Therefore it is an essential approach to search for a new kind of MOSFET gate dielectric materials with high dielectric constant to replace SiO₂. Among all of high-k materials studied, amorphous LaAlO₃ thin films with the pseudo-cubic perovskite structure will be the next-generation promising gate dielectric materials for MOSFET with high integration.In this thesis, amorphous LaAlO₃ thin films were firstly deposited on p-Si(100) substrates by Radio-frequency magnetron sputtering deposition. And the thickness measured by the way of double beam interference is about 150nm. After several months, LaAlO₃ thin films were post-annealed at different temperatures in atmosphere for 120 min, and then microstructure, chemical analysis and surface morphology of thin films were studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and Energy dispersive spectrometer (EDS) and so on. At last, the Pt/LaAlO₃/Si structure was prepared by Direct current magnetron sputtering deposition and was post-annealed at 650℃in O2 for 30 min. Good stability and electrical properties were shown by C-V and I-V characteristic curves of LaAlO₃ thin films.