气压对VHF-PECVD制备的μc-Si∶H薄膜特性影响的研究

本文主要研究了用VHF PECVD方法制备的不同工作气压的微晶硅薄膜样品。结果表明 :沉积速率随反应气压的增大而逐渐增大 ;光敏性 (光电导 /暗电导 )和激活能测试结果给出了相同的变化规律 ;傅立叶红外测试、X射线衍射和室温微区喇曼谱的结果都表明了样品的晶化特性 ;通过工艺的具体优化得出了器件级的微晶硅材料     

本征微晶硅薄膜和微晶硅电池的制备及其特性研究

本文对VHF-PECVD制备的本征微晶硅薄膜和电池进行了电学特性和结构特性方面的测试分析研究.电学测试结果给出制备薄膜的激活能为0.51eV,符合电池对材料的电学参数要求;拉曼散射谱测试结果计算得到样品的晶化率为63;;X射线衍射结果也证明材料晶化,同时(220)方向择优;首次在国内用VHF-PECVD方法制备出效率为5;的微晶硅电池(Jsc=21mA/cm2,Voc=0.46V,FF=51;,Area=0.253cm2).     

气压对VHF-PECVD制备的μc-Si:H 薄膜特性影响的研究

本文主要研究了用VHF-PECVD方法制备的不同工作气压的微晶硅薄膜样品.结果表明:沉积速率随反应气压的增大而逐渐增大;光敏性(光电导/暗电导)和激活能测试结果给出了相同的变化规律;傅立叶红外测试、X射线衍射和室温微区喇曼谱的结果都表明了样品的晶化特性;通过工艺的具体优化得出了器件级的微晶硅材料.     

氨水浓度对化学水浴法制备CdS缓冲层及CZTSe电池性能的影响

主要研究了化学水浴法沉积CdS薄膜中氨水浓度对薄膜材料特性的影响.通过X射线衍射(XRD)、扫描电子显微镜(SEM)和分光光度计(UV-Vis)等测试手段对制备的CdS薄膜的结构和光学特性进行了分析.结果表明:不同的氨水浓度条件下均得到立方相CdS薄膜,薄膜沿(111)面择优取向生长.随着氨水浓度增加时CdS薄膜表面逐渐变得致密光滑,CdS薄膜的透过率增强和带隙变宽.在氨水浓度为0.10 mol/L时制备出材料特性最佳的CdS薄膜,其表面紧凑致密无针孔,颗粒大小均匀,将其应用于CZTSe薄膜太阳电池中的缓冲层材料,得到光电转化效率为3.12;的CZTSe薄膜太阳电池(该电池未经任何后硒化处理工艺).     

VHF-PECVD沉积本征微晶硅薄膜激活能特性研究

采用激活能测试装置测量VHF-PECVD高速沉积的本征微晶硅薄膜,并对不同晶化率的样品和不同沉积功率、不同沉积压强条件下沉积制备的样品的激活能进行了分析研究.结果表明:在非晶-微晶相变域附近,激活能随着晶化率的升高而降低;随着沉积功率的增大和沉积气压的增大,沉积速率提高,样品的激活能升高,通过提高沉积功率和沉积气压可以有效的抑制氧污染.     

电子束蒸发法制备CdS薄膜光电特性研究

采用电子束蒸发法,以高纯CdS块料为膜料在玻璃基底上制备了CdS薄膜,设计了L9(34)正交实验,研究了各工艺参数对薄膜光电性能的影响.结果表明,随着基底温度,蒸发速率的提高,薄膜的电阻值呈降低趋势达到最小值后稍有升高;薄膜的阻值随真空度的降低而降低,达到一定程度后阻值基本保持不变.薄膜的暗亮电阻比即光敏性,随基底温度的增大先增大达到最大值后开始减小;而随蒸发速率的提高光敏性先缓后急的增加;真空度对光敏性的影响与蒸发速率对光敏性的影响正好相反,表现为随真空度的增加光敏性先急后缓的降低.正交实验表明:当基底温度为150℃,蒸发速率为1 nm·s-1,真空度为3×10-3 Pa时,薄膜的光电性能最好.CdS薄膜的光敏性达到7.7×102,其中亮电阻的最小值为1350Ω/□.     

微晶硅薄膜纵向不均匀性的Raman光谱和AFM研究

本文研究了采用VHF-PECVD技术制备的微晶硅薄膜的纵向均匀性.喇曼测试结果显示:微晶硅薄膜存在着生长方向的结构不均匀,随厚度的增加,材料的晶化率逐渐变大;不同衬底其非晶孵化点是不一样的,对于同一种衬底,绒度大相应的晶化率就大,对应着孵化层的厚度小;AFM测试结果明显的给出:材料的结构随厚度增加发生变化.     

非晶/微晶过渡区内材料性能及电池的研究

本文采用甚高频等离子增强化学气相沉积(VHF-PECVD)技术,通过调节硅烷浓度,获得了系列硅薄膜材料,并用拉曼散射光谱和X射线衍射光谱对材料的结构特性进行了测试分析,同时还使用原子力显微镜观察比较了薄膜的表面形貌。结果发现:在非晶/微晶过渡区内存在着一个光敏性较大的区域,这个区域内的材料晶化率为零,但是表面存在一些微小的晶粒;与拉曼散射光谱相比,X射线衍射光谱对微小的晶化更加敏感。以这部分材料作为太阳电池的本征层,在SnO2衬底上制备了p-i-n型太阳电池,电池的初始开路电压(Voc)达到了0.891V。     

直流磁控溅射工艺对ZnO薄膜结构影响的研究

ZnO是一种新型的Ⅱ-Ⅵ族直接带隙化合物材料,是一种很有潜力的短波长光电器件材料.当ZnO薄膜具有良好的c轴取向和晶格结构时,可得到优良的光电性能比如紫外光受激发射.本实验用XRD和SEM研究了工艺条件如基片温度、氩氧比及退火工艺对ZnO薄膜结构特性的影响.结果表明在基片温度250℃、氩氧比为1∶4的条件下,可得到结晶质量良好的ZnO薄膜;通过退火可以使薄膜应力得到驰豫,降低缺陷浓度,改善薄膜的结构特性.本实验采用直流磁控溅射的方法,最终在(100)硅衬底基片上制备出了高c轴取向、晶粒尺寸约70nm的ZnO薄膜.     

射频溅射功率对ZnO透明导电薄膜光电性能的影响

采用磁控溅射技术在不同溅射功率下制备了ZnO薄膜.研究了薄膜的沉积速率、光电特性以及不同功率条件下制备的ZnO薄膜对HIT电池开路电压的影响.结果表明:在溅射功率为200 W时制备的薄膜,具有良好的导电性和光透过性;将其应用到HIT电池中,得到的开路电压最高.该研究对提高HIT电池性能具有一定的参考意义.     

高压13.56MHz PECVD法沉积器件质量级本征微晶硅材料

本文国内首次报道了采用高压RF-PECVD技术沉积本征微晶硅材料的结果.实验表明,增大等离子体激发功率和减小硅烷浓度都能够使薄膜材料由非晶硅逐渐向微晶硅转变,而结构上的改变使得电学特性也随之改变.通过工艺参数的优化和纯化器的使用,有效地控制了氧的掺杂,在较高的生长速度下得到了器件质量级的本征微晶硅材料.将实验得到的微晶硅作为太阳电池光吸收层,在没有ZnO背电极和没有优化窗口层材料以及p/i界面时,电池的效率达到5.22;,这进一步表明本征微晶硅材料的良好性能.     

Effect of oxygen content on barrier properties of silicon oxide thin film deposited by dual ion-beam sputtering

A silicon oxide thin film barrier was prepared with various oxygen contents and its chemical composition, surface morphology and optical and barrier properties were related to the deposition conditions used. Our study showed that under Ar and O₂ assisted process conditions, a stoichiometric silicon oxide thin film formed at a critical oxygen content during deposition of 40-50%. The thin films deposited at the critical condition showed the lowest surface roughness giving similar or higher optical transmittance than that of the bare polycarbonate (PC) substrate. The boiling and tensile strength test performed on the thin film deposited with assisted ions before the deposition process showed improvement in the adhesion between the oxide layer and the polymer substrate. In addition, interface modification to improve for improving the barrier layer properties of the silicon oxide thin film was achieved through the introduction of dual ion beam sputtering without pre-treatment.     

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。     

Growth and optical property characterization of textured barium titanate thin films for photonic applications

We have investigated the growth of barium titanate thin films on bulk crystalline and amorphous substrates utilizing biaxially oriented template layers. Ion beam-assisted deposition was used to grow thin, biaxially textured, magnesium oxide template layers on amorphous and silicon substrates. Growth of highly oriented barium titanate films on these template layers was achieved by molecular beam epitaxy using a layer-by-layer growth process. Barium titanate thin films were grown in molecular oxygen and in the presence of oxygen radicals produced by a 300 W radio frequency plasma. We used X-ray and in situ reflection high-energy electron diffraction (RHEED) to analyze the structural properties and show the predominantly c-oriented grains in the films. Variable angle spectroscopic ellipsometry was used to analyze and compare the optical properties of the thin films grown with and without oxygen plasma. We have shown that optical quality barium titanate thin films, which show bulk crystal-like properties, can be grown on any substrate through the use of biaxially oriented magnesium oxide template layers.     

沉积氧压对Bi1.5ZnNb1.5O7薄膜的结构和介电特性的影响

采用固相反应法合成具有焦绿石立方结构的Bi1.5ZnNb1.5O7(BZN)陶瓷靶材,采用脉冲激光沉积法在Pt/SiO2/Si(100)基片上制备立方BZN薄膜。研究了沉积氧压的变化对薄膜的结晶性能,微观形貌以及介电性能的影响。结果表明:沉积的BZN薄膜都呈现出立方焦绿石单相结构,但是薄膜的取向随氧压变化而变化。当沉积氧压为10 Pa时,薄膜的(222)晶面拥有最强的择优取向。随着氧压的升高,BZN薄膜的介电常数明显降低。在10 Pa氧压下沉积的BZN薄膜展示出介电可调特性为5%(500 kV/cm)。     

Annealing effects of highly homogeneous a-Si1−xCx:H

We report the effect of annealing on the properties of amorphous hydrogenated silicon carbide thin films. The samples were deposited onto different substrates by plasma enhanced chemical vapor deposition at temperatures between 300 and 350 °C. The gaseous mixture was formed by silane and methane, at the ‘silane starving plasma regime’, and diluted with hydrogen. Rutherford backscattering and Fourier transform infrared spectrometry were used, respectively, to determine the atomic composition and chemical bonds of the samples. The film’s structure was analyzed by means of X-ray absorption fine structure and X-ray diffraction. For temperatures higher than 600 °C, amorphous silicon carbide films annealed under inert atmosphere (Ar or N₂) clearly changed their structural and compositional properties due to carbon loss and oxidation, caused by the presence of some oxygen in the annealing system. At 1000 °C, crystallization of the films becomes evident but only stoichiometric films deposited on single crystalline Si[1 0 0] substrates presented epitaxial formation of SiC crystals, showing that the crystallization process is substrate dependent. Films annealed in high-vacuum also changed their structural properties for annealing temperatures higher than 600 °C, but no traces of oxidation were observed or variations in their silicon or carbon content. At 1200 °C the stoichiometric films are fully polycrystalline, showing the existence of only a SiC phase. The XANES signal of samples deposited onto different substrates and annealed under high-vacuum also show that crystallization is highly substrate dependent.     

高气压下微晶硅薄膜的生长及微结构研究

通过射频等离子体增强化学气相沉积,在高气压条件下制备了微晶硅薄膜,并用拉曼光谱仪(Ram an)、扫描电镜(SEM)研究了微晶硅薄膜的微观结构。发现沉积速率在5Torr左右出现极大值,薄膜的晶化率随着沉积气压的升高而降低,薄膜表面的晶粒或团簇随着沉积气压的下降而增大,薄膜的粗糙度随着沉积气压的升高而降低。     

氧分压对HfOxNy薄膜结构和力学性能的影响

采用射频磁控反应溅射法在不同氧分压条件下制备了氮氧化铪薄膜,薄膜沉积过程在氧气、氮气和氩气的混合气氛中进行,所用衬底为多光谱硫化锌材料.用X射线衍射、扫描电子显微镜、纳米硬度计等分别研究了不同氧分压条件下HfOxNy薄膜的晶体结构、显微结构、力学性能等.结果表明:在氧分压为0.05～0.30范围内,HfOxNy薄膜都为多晶结构,但随着氧分压的降低,HfOxNy薄膜的沉积速率逐渐增大,薄膜的晶体结构由单斜氧化铪转变为氮氧化铪相;不同氧分压下沉积的HfOxNy薄膜都符合薄膜区域结构模型中典型的柱状结构且氧分压较低时薄膜表面粗糙度较大;不同氧分压条件下沉积的HfOxNy薄膜硬度和弹性模量都远大于衬底硫化锌的硬度和弹性模量,氧分压为0.15时最大硬度和弹性模量值分别为11.6 GPa和160 GPa.     

Synthesis of polycrystalline silicon thin films with ‘icosahedral’ symmetry by ceramics hot wire chemical vapor deposition

We report on synthesis and materials physics of polycrystalline silicon thin films deposited on glass with rarely observed ‘five-fold’ symmetry or ‘icosahedral’ symmetry. We invented these ‘novel form’ of polycrystalline silicon thin films by ceramics hot wire chemical vapor deposition (hot-wire CVD). A new physical effect in hot-wire CVD technology has been proposed that controls the nucleation and growth of silicon thin films on glass substrate.