用CeO2陶瓷靶材,使用脉冲激光沉积(PLD)技术在Si(100)衬底上制备了CeO2薄膜。研究了衬底温度、沉积氧压对薄膜性能的影响,实验制备出了高度(111)取向的CeO2薄膜。使用X射线衍射(XRD)、反射式高能电子衍射(RHEED)对薄膜进行晶体结构的表征。结果表明:随着衬底温度的增加,薄膜中的残余宏观应力(拉应力)及微观应力逐渐减小,薄膜结晶质量不断提高,而沉积氧压对此影响较小。RHEED图像显示使用PLD方法在Si衬底上沉积的薄膜具备较高的结晶性及原子级平整的表面。使用原子力显微镜(AFM)对样品进行表面粗糙度分析,发现不同温度下生长的薄膜均具有光滑的表面,方均根粗糙度(RMS)均在0.4nm以下。使用Keithley4200半导体测试仪、椭偏仪对薄膜进行电性能及光学性能分析,发现衬底温度对薄膜的电学性能有显著影响,并且CeO2薄膜结晶状态与电学性能有直接的联系。
Thin films of CeO2 were grown on Si(100) single crystal substrates by pulsed laser deposition using CeO2 ceramic target. The influence of substrate temperature and oxygen pressure on the properties of the film was studied. Strong preference for CeO2 ( 111 ) orientation thin film was achieved. The structural characteristics of CeO2 thin films were characterized by X-ray diffraction (XRD), reflection high-energy electron diffraction (RHEED). Experimental results showed that macro-stress and micro-stress in the film decreased with the increase of substrate temperature while deposition pressure had little influence on this. RHEED image showed that a perfect crystallinity and smooth surface were achieved by PLD. Based on the AFM analysis, all the RMS of the films deposited at different temperatures were less than 0.4 nm and almost independent with substrate temperature. The electrical and optical characteristics of the film were analyzed by using Keithley 4200 and ellipsome.ter, respectively. The results showed that substrate temperature had significant influence on the electrical characteristics of CeO2 thin film and the direct relationship between electrical characteristics and crystallinity was proved.