论文标题:多晶氧化锌薄膜的制备和结构、电学、光学特性研究
Study on Preparation and Structural, Electrical and Optical Properties of Polycrystalline Zinc Oxide Films
论文作者 龚恒翔
论文导师 王印月,论文学位 博士,论文专业 凝聚态物理
论文单位 兰州大学,点击次数 161,论文页数 125页File Size998k
2002-05-01论文网 http://www.lw23.com/lunwen_39861392/ 弹性波;摩擦;单侧接触;界面;埋置结构;动力相互作用;边界非线性;瞬态时域边界元法
1 Elastic Wave;Friction;Unilateral Contact;Interface;Embedded Structure;Dynamic Interaction;Boundary Nonlinearity;Transient Tim-Domain Boundary Element Method
多晶氧化锌(ZnO)薄膜是一种多功能宽带隙氧化物半导体薄膜材料,它可以作为透明导电薄膜、压电薄膜、光电子器件、气敏和湿敏器件而具有广泛的应用前景,已经引起了越来越多研究者的关注。本论文主要工作是多晶ZnO薄膜的制备和结构、电学、光学特性研究。采用射频反应溅射法,以高纯度O2和Ar 为溅射工作气体,成功地在不同衬底材料上制备得到了高质量的多晶ZnO 薄膜。溅射靶采用高纯度金属锌是本研究工作的特点,与大多数研究者采用的ZnO 陶瓷靶相比,金属靶具有不易污染和制作成本低的特点。创造性地通过Al 与Zn 复合靶成功地共溅射制备得到Al 掺杂多晶ZnO 薄膜是本研究工作的另一特点,采用这种方法通过改变复合溅射靶上高纯度Al 块的数目可以方便地调整Al 掺杂剂量。系统地研究了沉积条件对多晶ZnO 薄膜结构的影响。通过分析衬底温度、溅射工作气体组分、溅射功率和衬底位置对样品结构的影响,得到了样品最佳制备条件:衬底温度400℃、溅射功率120W、溅射工作气体中O2分压比40%。最佳制备条件下样品具有高度的透明性(优于86%,波长3000?~11000?)和(002)方向取向性,(002)衍射峰半高宽仅仅0.2deg,薄膜堆积密度高达97%。原子力显微镜(AFM)分析表明薄膜具有密集堆积的均匀柱状晶粒,X 射线光电子谱证明了薄膜中杂质Al 的存在,Al 掺杂多晶ZnO 薄膜最低电阻率达到10-4Ωcm 数量级。同时也关注了存在于薄膜中(002)晶面的压应力,发现此应力随着衬底温度升高而单调减小。观察到溅射靶表面存在环形过度氧化区域,分析认为此区域的存在是等离子体中O 原子和O-离子分布的不均匀性造成的,它是材料结构、电学和光学特性随衬底位置不同而变化的根本原因。
Polycrystalline zinc oxide(ZnO) films are one of very useful materials and arewidely used in piezoelectric device, transparent conducting electrodes,optoelectric device and gas sensors because of their excellent characteristics. Inthis dissertation, we report the systematical work on preparation, and thestructural, electrical, and optical properties of polycrystalline ZnO films.ZnO films were deposited on silicon(Si) and glass substrate by reactive radiofrequency sputtering(RF) technique with zinc target in the mixed gas of Ar andO2. Zinc target has obvious advantage over ZnO targets used by otherresearchers because of little contamination and low cost. A creative co-sputtering method of lying some aluminum(Al) chips on target was employed todeposit Al-doped ZnO films(AZO). In this way, the Al content in films can becontrolled easily compared with that of ZnO target.The effect of deposition condition, included RF power, substrate temperature,the ratio of O2 to Ar in mixed gas and the position of substrate on the structuralproperties of ZnO films has be studied in considerable detail. It is found that theoptimal conditions to deposit ZnO are below: substrate temperature of 400, RFpower of 120W, and the ratio of O2 to Ar of 40%. The average opticaltransmittance in the wavelength range from 3000? to 11000?, the full width athalf maximum(FWHM)and the packing density of ZnO films are 86%, 0.2deg.and 97%, respectively. The surface morphology shows a closed-packedcolumnar grain indicated by atomic force microscope(AFM). X-rayphotoelectron spectrometer(XPS) analysis indicated the existence of Al. Thefilms have a highly oriented growth characteristics with the c-axis perpendicular
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