脉冲激光沉积法制备钛酸锶钡薄膜及性能研究

发布时间：2018-03-23 11:01

  本文选题：脉冲激光沉积　切入点：BST薄膜　出处：《西安理工大学》2017年硕士论文

【摘要】：Ba1-xSrxTiO3(BST)薄膜材料因具有较高的介电常数及优良的介电非线性效应,在动态随机存储器(DRAM)及电压可调微波器件等方面具有良好的应用前景。为了与半导体工艺兼容,Si基BST薄膜成为当前研究热点之一。目前这类BST薄膜存在的主要问题是薄膜的介电损耗较高,难以达到应用要求,而掺杂改性成为试图解决这类问题的重要手段。本文首先采用固相反应法制备不同浓度Mn掺杂的Ba0.5Sr0.5TiO3陶瓷,作为脉冲激光沉积(PLD)法制备Ba0.5Sr0.5TiO3薄膜材料的靶材,随后在Si(001)基片上探究了 BST/LNO/Si的制备工艺,并研究了 Mn掺杂对BST薄膜性能的影响。主要研究成果如下:(1)首先通过固相反应法制备了Ba0.5Sr0.5TiO3陶瓷,研究了烧结温度对陶瓷靶材性能的影响并确定1300 ℃为最终烧结温度。随后制备了不同浓度Mn掺杂BST陶瓷,研究Mn掺杂浓度对BST陶瓷性能的影响。发现Mn掺杂会影响BST陶瓷的介电性能,样品介电常数随Mn掺杂浓度升高而降低,介电损耗随掺杂浓度升高先减小后增大。(2)采用自制靶材,在制备好的LNO/Si上用PLD法沉积BST薄膜,研究了 PLD法制备BST薄膜过程中沉积气压、激光能量和脉冲频率对薄膜结构的影响,确定了 BST薄膜最优的生长工艺为衬底温度650 ℃、氧分压5 Pa、激光能量220 mJ、脉冲频率2 Hz、沉积时间 60 min、靶基距离 45 mm。。(3)研究了 Mn掺杂浓度变化对BST薄膜介电性能的影响。结果发现Mn掺杂薄膜样品与陶瓷样品的介电性能随掺杂浓度变化有着相似的规律,即薄膜介电常数随Mn掺杂浓度升高而降低,介电损耗随掺杂浓度先减小后增大。另外,Mn掺杂起到了改善BST薄膜漏电流的作用。结果表明BST薄膜在掺杂浓度为2 mol%时介电性能相对较好。
[Abstract]:Ba1-xSrxTiO3BST thin films have high dielectric constant and excellent dielectric nonlinear effect. It has a good application prospect in dynamic random access memory (RAM) and voltage-adjustable microwave devices. In order to be compatible with semiconductor technology, BST thin films on Si substrates have become one of the current research hotspots. At present, the existence of this kind of BST thin films is mainly discussed. The problem is that the dielectric loss of the film is high. It is difficult to meet the requirements of application, but doping modification has become an important means to solve this problem. Firstly, Mn-doped Ba0.5Sr0.5TiO3 ceramics with different concentrations were prepared by solid-state reaction method, which were used as targets for preparing Ba0.5Sr0.5TiO3 thin films by pulsed laser deposition. Then the preparation process of BST/LNO/Si and the effect of mn doping on the properties of BST thin films were investigated on the Si Si 001) substrate. The main research results are as follows: firstly, Ba0.5Sr0.5TiO3 ceramics were prepared by solid state reaction. The effect of sintering temperature on the properties of ceramic targets was studied and the final sintering temperature was determined at 1300 鈩，

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