Investigation Of Preferred Orientation Of SrTiO₃Film Fabricated On Single Crystal Si Substrate

Single crystal Si, with excellent electrical and mechanical properties, is one of important semiconductor materials. Because of its good chemical stability, expected structure and excellent dielectric properties, SrTiO3(STO) integrated with Si is highly desirable for future generation transistor gate dielectric. Furthermore, for heterogeneous epitaxial growth of various functional oxide films on Si substrate, high-quality STO film is usually used as transition layer.In this paper, Liquid phase deposition(LPD) and RF magnetron sputtering were adopted to obtain STO film by the original and modified Si(100) substrate. The quality STO film was improved by optimizing experimental parameters. The main contents of the paper are as follows:1. Liquid phase deposition method. Hydrophilic time, deposition temperature and annealing temperature were studied to improve the morphology and crystallinity of STO film. The results of XRD and SEM revealed that the quality of STO film prepared via LPD depended on the wettability of substrate surface, and the wettability was desirable when the hydrophilic time was10min. In the process of mixing up precursors, boric acid should be added slowly. Smooth STO film was obtained when the deposition temperature was40℃, followed by annealing at650℃for4h, and large grains appeared while increasing the deposition temperature.2. RF magnetron sputtering. The effect of heat treatment conditions and sputtering parameters on growth orientation and surface morphology of STO film was studied. The results of XRD and SEM indicated that STO film with (e00) preferred orientation was obtained when the substrate temperature was300℃via RF magnetron sputtering, followed by post annealing at700℃, which was optimal annealing temperature. The increase and decrease of substrate temperature or annealing temperature would deteriorate the preferred orientation, while annealing with long time could cause interfacial reaction and decomposition. The decrease of sputtering power and pressure improved the degree of preferred orientation of STO film.STO film prepared by LPD had not obvious preferred oriention and showed polycrystalline, which could not meet requirements of good gate dielectric or transition layer. Utilizing RF magnetron sputtering technology, STO film with maximum (e00) preferred orientation could be used as good transition layer. When modified single crystal Si(100) was used as substrate, crystallinity of STO film obtained on sidewalls of V-grooves need to be confirmed.