热丝法低温制备多晶硅薄膜微结构的研究

采用热丝化学气相沉积法(HFCVD)在普通玻璃衬底上低温沉积多晶硅薄膜。利用XRD、拉曼光谱和原子力显微镜(AFM)研究了灯丝与衬底间距(5~10mm),灯丝温度(1800~1400℃)和衬底温度(320~205℃)对薄膜晶体取向、晶化率、晶粒尺寸以及形貌的影响规律。结果表明,随着热丝与衬底间距增加,多晶硅薄膜的晶化率和晶粒尺寸明显减小;随热丝温度的降低,薄膜的晶化率都出现了大致相同的规律:先不断增大后突然大幅减小。     

石墨衬底上铝诱导法制备多晶硅薄膜

利用磁控溅射技术在石墨衬底上制备了石墨/a-Si/Al和石墨/Al/a-Si叠层结构,采用常规退火(CTA)和快速热退火(RTA)对样品进行退火,系统研究了不同退火条件对多晶硅薄膜制备的影响.利用X射线衍射(XRD),拉曼光谱(Raman)对制备的多晶硅薄膜进行表征,并利用谢乐公式计算了晶粒尺寸,结果表明制备的多晶硅薄膜具有高度(111)择优取向,结晶质量良好,利于后续外延制作多晶硅厚膜电池.基于实验结果,建立了铝诱导晶化模型,很好的解释了实验现象.     

电场辅助铝诱导晶化非晶硅薄膜

以氢气稀释的硅烷和氢气为反应气体,利用PECVD法先在玻璃衬底上生长非晶硅薄膜,然后利用磁控溅射法在非晶硅薄膜上镀制铝膜,最后将镀有铝膜的非晶硅薄膜样品置于快速热处理炉中,在外加电场辅助条件下,在氮气气氛下对薄膜样品进行退火制备多晶硅薄膜.本论文研究了不同外加电场强度和退火时间对非晶硅薄膜晶化的影响.利用XRD、SEM和Raman等测试方法对薄膜样品的晶相结构、表面形貌和晶化程度进行了表征.实验结果表明,在外加横向电场辅助铝诱导晶化的条件下,非晶硅薄膜在500 ℃低温下成功地转化成多晶硅薄膜,并且随着横向电场强度的增大以及退火时间的延长,薄膜的晶化程度增强,晶粒尺寸增大.     

铝诱导纳米硅制备大晶粒多晶硅薄膜的研究

本文以超白玻璃为衬底,利用热丝化学气相沉积和磁控溅射法制备了Glass/nc-Si/Al的叠层结构,然后置于管式退火炉中在H2气氛下进行5h诱导晶化,用XRD、光学显微镜、扫描电镜和拉曼光谱对样品进行了表征.结果表明所有样品都是有(111)择优取向的多晶硅薄膜,在425℃诱导时,多晶硅晶粒尺寸最大达400 μm,但薄膜不连续;随着诱导温度升高到450℃,样品表面已形成了连续的多晶硅薄膜,但晶粒尺寸有所减小;475℃下诱导获得的最大晶粒尺寸约为200μm,此时多晶硅薄膜的结晶质量更好.还从动力学的角度分析了铝诱导纳米硅的晶化机理.     

PECVD低温制备微晶硅薄膜的研究

实验采用等离子体增强化学气相沉积(PECVD)法在玻璃衬底上制备了微晶硅薄膜.研究了氢稀释比、衬底温度、射频功率等因素对薄膜晶化的影响,得出在一定范围内随着衬底温度的升高、射频功率和氢稀释比的增大,薄膜的晶化率得到提高;但进一步提高沉积温度、射频功率反而会使薄膜晶化效果变差,并对晶化硅薄膜低温生长的机理进行了初步的探讨.     

PECVD法制备不同衬底微晶硅薄膜的研究

采用等离子体增强化学气相沉积(PECVD)法分别在玻璃衬底和p型薄膜硅衬底上制备了微晶硅薄膜。使用拉曼谱仪、紫外-可见分光光度计、傅里叶红外光谱仪等对微晶硅薄膜进行检测,重点研究了硅烷浓度、衬底温度对薄膜沉积速率和晶化率的影响。实验结果表明:两种衬底上薄膜的沉积速率均随硅烷浓度的增大、衬底温度的升高而变大。硅烷浓度对两种衬底的薄膜晶化率影响规律相同,即均随其升高而降低;但两种衬底的衬底温度影响规律存在差别:对玻璃衬底而言,温度升高,样品晶化率减小;而p型薄膜硅衬底则在温度升高时,样品晶化率先增大后减小。此外还发现,晶化率与薄膜光学性能及含氧量存在较密切关联。     

对柱状多晶硅薄膜的制备研究

在多晶硅薄膜(Poly-Si)生长理论的基础上,用等离子体化学气相沉积(RF-PECVD)系统,配合快速光热退火装置(RTP),在玻璃衬底和石英衬底上制备了柱状结构的多晶硅薄膜.借助于扫描电子显微镜(SEM)等测试手段,对薄膜的表面形貌和断面形貌进行了分析.结果发现:(1)柱晶的形成对薄膜的厚度有一定要求,而且薄膜越厚,柱晶直径越容易长得更大.本实验中,薄膜厚度达到2.5μm左右时,柱晶直径达到了1.5μm以上;(2)再结晶过程是从靠近光源的薄膜表面开始进而到薄膜内部的.再次说明RTP中再结晶的发生,与光和物质的相互作用密切相关.     

多晶硅薄膜结晶团晶化机理的研究

本文用PECVD法在石英玻璃上沉积非晶硅薄膜,然后用快速光退火和传统电阻炉退火方法晶化生长多晶硅薄膜,用拉曼光谱仪、XRD和场发射扫描电镜观察分析薄膜,发现在制备的多晶硅薄膜表面存在结晶团现象,并对这一现象的晶化机理进行了分析.     

单晶硅外延生长晶化硅薄膜的研究

采用P型单晶硅片为衬底,并经混合酸溶液腐蚀抛光、清洗后,利用射频磁控溅射镀膜系统在其表面制备非晶硅薄膜;再结合快速光热退火工艺,于N2气氛下480℃退火30 min,得到晶化硅薄膜;利用光学金相显微镜、XRD衍射仪和拉曼散射光谱(Raman)仪对单晶硅衬底和晶化硅薄膜进行结构和性能表征.研究了混合酸溶液对单晶硅表面腐蚀效果、籽晶诱导外延生长晶化硅薄膜的物相结构和薄膜带隙.结果表明:采用混合酸溶液腐蚀后得到表面平整、光滑的单晶硅衬底;非晶硅薄膜经过快速退火后受籽晶诱导生成晶化硅薄膜,其晶相沿单晶硅衬底取向择优生长;随着非晶硅薄膜厚度从80 nm增加到280 nm,晶化后硅薄膜的表面粗糙度逐渐减小,晶化率从90.0;逐渐降低到37.0;;晶粒尺寸从6.65 nm逐渐减小到1.71 nm;带隙从1.18 eV逐渐升高到1.52 eV.     

基于PECVD制备多晶硅薄膜研究

基于PECVD以高纯SiH4为气源研究制备多晶硅薄膜,在衬底温度550℃、射频(13.56MHz)电源功率为20W直接沉积获得多晶硅薄膜.采用X射线衍射仪(XRD) 和场发射扫描电子显微镜(SEM) 对多个样品薄膜的结晶情况及形貌进行分析,薄膜结晶粒取向均为<111>、<220>、<311>晶向.对550℃沉积态薄膜在900℃、1100℃时进行高温退火处理,硅衍射峰明显加强.结果表明,退火温度越高,退火时间越长,得到多晶硅薄膜表面晶粒趋于平坦,择优取向为<111>晶向,晶粒也相对增大.     

衬底温度对共蒸发制备GaSb多晶薄膜性质的影响

采用共蒸发的方法在玻璃衬底上制备出GaSb多晶薄膜材料.研究了薄膜生长速率与衬底温度、Ga源温度和Sb源温度的关系.通过XRD、UV-Vis、Hall效应和AFM等测试方法,研究了衬底温度对于GaSb薄膜的结构特性、光电性质以及表面形貌的影响.GaSb多晶薄膜具有(111)择优取向,薄膜的吸收系数达到105 cm-1,晶粒尺寸随衬底温度升高逐渐增大;衬底温度为540℃时,薄膜的迁移率达到127 cm2/V·s,空穴浓度为3×1017 cm-3.GaSb薄膜的表面粗糙度随温度增加而增加.     

Thickness Dependence of Electrical and Structural Properties of FTO Films

Fluorine (0.8 M) doped tin oxide films of various thicknesses were prepared on heated glass substrates (520 °C) by spray pyrolysis technique. The chemical and thermal stabilities of FTO films were found to be very good. The characterization has been done by XRD and found to agree with the reported results. As thickness of the film increases, intensities of peaks increased. From the X-ray diffraction data, grain size of the crystallites have been calculated. The electrical and structural properties were studied for different thicknesses. Hall measurements showed that thicker films have relatively high Hall mobilities compared to those of thinner films. The high carrier concentration showed that the films are degenerate. The relationship between carrier concentration and Hall mobility revealed that the ionized impurity scattering centres were the dominant cause of scattering.     

Preparation of CeO2-TiO2 coatings by the sol-gel process

Yellow coatings have been prepared from titanium tetraisopropoxide and cerium chloride by the sol-gel dip-coating process, and the transmittance, chromaticity, thickness and acidic durability of the coating films produced on glass or aluminum were studied. The effects of the pH of the solution on the preparation of the transparent and homogeneous coating films were studied by adding the alkali or acid, and as a result transparent and homogeneous yellow coating films were prepared by dipping the substrate in a solution containing acetic acidic solution. The acidic durability of the aluminum foil was improved by dip-coating the brilliant yellow CeO₂-TiO₂ coating three times.     

高硼硅玻璃薄膜的磁控溅射沉积及性能研究

本文采用射频磁控溅射法,以高硼硅玻璃为靶材,在高硼硅玻璃基底上制备高硼硅玻璃薄膜。探讨磁控溅射法与熔融法制得的高硼硅玻璃的性能差异,研究磁控溅射功率对高硼硅玻璃薄膜质量的影响。通过X射线衍射仪(XRD)、傅里叶红外光谱仪(FT-IR)、X射线光电子能谱仪(XPS)、扫描电镜(SEM)、台阶仪、紫外可见(UV-Vis)分光光度计和纳米压痕仪器等对薄膜的物相结构、成分、沉积速率、透光率,以及纳米硬度和杨氏模量进行表征与分析。结果表明:本实验所制备的高硼硅玻璃薄膜为非晶态结构;当工作气压为0.6 Pa时,薄膜的沉积速率随溅射功率上升不断增加;对比不同溅射功率下的透光率,发现高硼硅玻璃薄膜对基体的透光性影响较小,当溅射功率为150 W,可见光透光率损失仅为2%;不同溅射功率下获得薄膜的纳米硬度和杨氏模量随溅射功率先增大后减小,在120 W时达到最大峰值,相较于原玻璃基底分别提升3%和3.5%。     

Substrate effect on microstructure and optical performance of sputter‐deposited TiO2 thin films

This study deals with the role of the different substrates on the microstructural, optical and electronical properties of TiO₂ thin films produced by conventional direct current (DC) magnetron sputtering in a mixture of pure argon and oxygen using a Ti metal target with the aid of X–ray diffractometer (XRD), ultra violet spectrometer (UV–vis) and atomic force microscopy (AFM) measurements. Transparent TiO₂ thin films are deposited on Soda lime glass, MgO(100), quartz and sitall substrates. Phase purity, surface morphology, optical and photocatalytic properties of the films are compared with each other. It is found that the amplitude of interference oscillation of the films is in a range of 77‐89%. The transmittance of the film deposited on Soda lime glass is the smallest while the film produced on MgO(100) substrate obtains the maximum transmittance value. The refractive index and optical band gap of the TiO₂ thin films are also inferred from the transmittance spectra. The results show that the film deposited on Soda lime glass has the better optical property while the film produced on MgO(100) substrate exhibits much better photoactivity than the other films because of the large optical energy band gap. As for the XRD results, the film prepared on MgO(100) substrate contains the anatase phase only; on the other hand, the other films contain both anatase and rutile phases. Furthermore, AFM images show that the regular structures are observed on the surface of all the films studied. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

溶剂热法制备Al掺杂ZnO薄膜的机理研究

采用溶剂热法在玻璃衬底上制备Al掺杂的ZnO薄膜,研究了溶剂热过程中升温、恒温和降温三个阶段分别对薄膜物相和形貌的影响,探讨了薄膜的生长机理.结果表明,升温阶段只是形核过程,基片仅在升温阶段与前驱液接触不能形成薄膜;基片在升温-恒温阶段与前驱液接触可制备(002)择优取向的薄膜;恒温阶段既有成核过程又有晶体生长过程,基片仅在恒温阶段与前驱液接触可以制备薄膜;降温阶段薄膜继续生长.     

膜厚对Zr,Al共掺杂ZnO透明导电薄膜结构和光电性能的影响

采用直流磁控溅射法在玻璃衬底上制备出Zr,Al共掺杂ZnO(AZZO)透明导电薄膜.用XRD和SEM分析和观察了薄膜样品的组织结构和表面形貌.研究表明:制备的AZZO透明导电薄膜为六角纤锌矿结构的多晶薄膜,且具有c轴择优取向.另外还研究了薄膜的结构、光学和电学性质随薄膜厚度的变化关系.当薄膜厚度为843 nm时,电阻率具有最小值1.18×10~(-3) Ω·cm,在可见光区(500～800 nm)平均透过率超过93;.     

TiO2 thin films as sensing gas materials

TiO₂ thin films were prepared by DC reactive magnetron sputtering on heated Si, quartz and glass substrates using O₂ and water vapor as reactive gases. The percentage of anatase and rutile as well as the grain size strongly depend on the deposition conditions, as revealed by X-ray diffraction patterns. The films deposited on Si substrates are pure rutile, while a mixed anatase/rutile structure occurs in the films deposited on glass and quartz substrates. Smaller grain rutile and anatase films were prepared in a water vapor atmosphere, in contrast to the films grown in oxygen. The former choice considerably increases the sensing properties of titanium dioxide films. The gas sensitivity was investigated for some reducing gases (methane, acetone, ethanol and liquefied petroleum gas) and the optimum operating temperatures were found.     

固溶体半导体碲硫锌多晶薄膜的制备及发光特性研究

ZnS1-x Tex薄膜具有高效的发光特性.样品可观测到强烈的光致发光,随着Te含量x的不同,发射光的颜色从深蓝到黄变化,使其成为制作短波长光波段光电子器件和紫外探测器的理想材料.本文介绍了ZnS1-x Tex多晶薄膜真空蒸发制备的情况,并用X射线衍射仪对淀积在玻璃、石英玻璃和单晶硅衬底上的多晶薄膜进行结构分析,用紫外-可见分光光度计、荧光光谱分析仪对样品的光吸收和发光性质进行研究.分析表明,该薄膜的结构符合闪锌矿的特征.紫外-可见吸收光谱显示该样品在紫外光区有一个强烈的吸收峰,可见光区的吸收很微弱.光致发光光谱表明,样品在可见光区有一个以470nm为中心的发射峰,发射光肉眼可见.该多晶薄膜基本保持了单晶薄膜的紫外吸收、光致发光等良好特性.     

衬底温度对直流反应磁控溅射法制备的N掺杂p型ZnO薄膜性能的影响

利用直流反应磁控溅射法(纯金属锌作为靶材,Ar-N2-O2混合气体作为溅射气体)在石英玻璃衬底上制备了N掺杂p型ZnO薄膜.通过XRD、Hall和紫外可见透射谱分别研究了衬底温度对ZnO薄膜结构性能、电学性能和光学性能的影响.XRD结果显示所有制备的薄膜都具有垂直于衬底的c轴择优取向,并且随着衬底温度的增加,薄膜的晶体质量得到了提高.Hall测试表明衬底温度对p型ZnO薄膜的电阻率具有较大影响,400℃下生长的p型ZnO薄膜由于具有较高的迁移率(1.32 cm2/Vs)和载流子浓度(5.58×1017cm-3),因此表现出了最小的电阻率(8.44Ω·cm).