MOCVD技术在MgO基底沉积YBCO薄膜缓冲层LaMnO_(3)研究

Research on LaMnO_(3)buffer layer of YBCO thin film deposited on MgO substrate using MOCVD

在MgO基底使用金属有机化学气相沉积(MOCVD)法直接制备YBa_(2)Cu_(3)O_(7-δ)会出现MgO和YBCO晶格失配较大的问题,从而影响薄膜的生长和超导器件的制备。缓冲层的引入是一种可靠的解决手段。本文基于MOCVD技术,在MgO基底上生长LaMnO_(3)缓冲层,用以解决YBCO薄膜混合生长模式的问题,并通过改变MOCVD系统的氧气流量和沉积温度等沉积参数,采用如XRD,SEM,AFM等多种分析测试方法研究LMO缓冲层的结构取向和表面形貌。结果表明:当沉积温度为800℃,氧气流量为1000 sccm时,所制备的LMO缓冲层的结构取向最佳,缓冲层上生长的YBCO薄膜Ф扫描曲线出现四个相距90°的独立尖峰,YBCO在LMO缓冲层上只有一种生长方向,LMO缓冲层能够解决YBCO在MgO衬底上混合生长模式的问题,从而提高YBCO薄膜质量和性能。

Direct preparation of YBa_(2)Cu_(3)O_(7-δ)using MOCVD method on MgO substratecan lead to significant lattice mis⁃match between MgO and YBCO,which affects the growth of thin films and the preparation of superconducting devices,so the use of buffer layers is a reliable solution.Based on MOCVD technology,LaMnO_(3)buffer layer was grown on MgO substrate to solve the problem of mixed growth mode of YBCO thin films.By changing the deposition parameters such as oxygen flow rate and depo⁃sition temperature in the MOCVD system,various analysis and testing methods such as XRD,SEM,AFM were used to research the structural orientation and surface morphology of the LMO buffer layer.The experimental results show that when the deposition temperature is 800℃and the oxygen flow rate is 1000 sccm,the structural orientation of the LMO buffer layer prepared is the best and theФscan of YBCO thin films grown on the buffer layer shows four independent peaks spaced 90°apart,indicating that YBCO has only one growth direction on the LMO buffer layer.Therefore,the LMO buffer layer can solve the problem of mixed growth modes of YBCO on MgO substrates and improve the quality and performance of YBCO thin films.