氧压对脉冲激光沉积LaNiO_3薄膜结构和电学性能的影响

Effect of oxygen pressures on microstructure and electrical property of LaNiO_3 thin films by PLD

通过改变氧分压,利用脉冲激光沉积方法在Si(100)衬底上制备了系列LaNiO3导电氧化物薄膜;经XRD测试研究发现,通过调控氧压,可获得具有高(100)取向薄膜,且氧压对薄膜结晶性有很大影响,在氧分压为7.5Pa时获得结晶性最好的薄膜。经XRF分析表明,La、Ni元素化学成分计量比随氧压增大而减小。经四探针法测试,薄膜电阻率最小为2.03×10-4Ω.cm,表现出了良好的金属导电性。经SEM和AFM分析表明,薄膜晶粒为柱状晶,排列均匀致密,薄膜表面均匀,粗糙度较小,表明LaNiO3薄膜可以用作一种良好的铁电薄膜底电极材料。

LaNiO3 thin films were deposited on Si （100） substrate by pulsed laser deposition（PLD）with different oxygen pressures. X-ray diffraction （XRD） analysis show that the LaNiO3 thin films have highly （100）-oriented hy controlling oxygen pressures. Oxygen pressures have a great in{luence on the crystallinity of the LaNiO3 thin films ,and the film has the best crystallinity when the oxygen pressure is 7.5Pa, the stoichiometric ratio of La to Ni element go down as the growing of oxygen pressures, the smallest resistivity of the LaNiO3 thin films is 2.03 ×10-4Ω·cm, it shows a good conductivity of metallic perovskite oxide; SEM and TEM analysis show that crystal grain of the film is columnar morphology, revealed smooth dense surfaces and very homogeneous grain distribution. Compacted and clearly well-defined grain size can also be observed. RMS of LaNiO3 films is 1.73 nm, which could be acceptable for most of the possible applications of LaNiO3 , for example as an electrode in ferroelectric（FE） thin films.