高速沉积氮化硅薄膜对其化学键及性能的影响

采用等离子增强型化学气相沉积法(RF-PECVD),源气体为NH3/SiH4/N2的混合气体,在330℃的温度下沉积a-SiNx∶H薄膜。研究表明在反应气体流量一定的情况下,反应腔气压对薄膜沉积速率影响最大。采用Fourier红外吸收光谱技术分析a-SiNx∶H薄膜中化学键结构,随着沉积速率的提高,薄膜的化学键结构发生变化,N—H键含量和氮含量增大,Si—H键含量和氢含量降低。薄膜沉积速率是影响薄膜物理和光学性质的重要工艺参数。禁带宽度(E04)主要受薄膜中氮原子含量的调制,随着沉积速率增大,氮原子含量增大。另外,介电常数和折射系数则随之增大。最后得到满足薄膜晶体管性能要求的最佳工艺参数。     

CeO2薄膜折射率与其聚集密度的关系式

一般蒸镀光学薄膜几乎都呈现微观柱状结构,这种薄膜的折射率随着聚集密度的改变而发生变化.     

退火温度对ZnO薄膜结晶和折射率的影响

采用磁控溅射法在石英衬底上制备出结晶性良好的氧化锌薄膜,并在氧气气氛中不同温度(100~800℃)下进行退火处理。然后利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)及椭偏仪对其结晶性能和光学性能进行了表征,探讨了退火温度对薄膜光学性能的影响,并分析其原因。研究表明:退火可以使c轴生长的薄膜取向性增强;同时晶粒尺寸增大,表明粗糙度也会增加。所测得的薄膜折射率变化范围为1.775~2.059,其中退火温度为500℃时对应相同波长的折射率最大,变化范围为1.894~2.059。     

PLD法薄膜沉积条件对ZnO薄膜特性的影响

介绍了基于PLD方法制备的ZnO薄膜,在衬底温度（200-400℃）改变的情况下,分别对薄膜的表面结构和光致发光的情况做了研究,发现其相关特性并得出了制备薄膜的最佳条件。     

射频磁控溅射法沉积非晶InGaZnO薄膜及真空退火对其性能的影响

采用RF磁控溅射法在石英玻璃上制备了InGaZnO薄膜,并对薄膜进行了真空退火实验,探讨了沉积过程中氧气流量及真空退火温度对薄膜的光学性质和电学性质的影响及其机理。测试结果表明薄膜的光透过率随氧气流的增加而增大,且当氧气流大于1cm3/min时,薄膜呈现出不导电性,在通入的氧气流为0.5cm3/min时迁移率达11.9cm2/(V·s)。经过真空退火后,氧气流小于1.5cm3/min时薄膜载流子浓度随退火温度的变化而变化;氧气流大于1.5cm3/min时样品由半绝缘性转变为半导电性。生长样品和退火样品均为n型半导体。     

沉积条件对氢化锂薄膜形貌和沉积速率的影响

为了研究沉积条件对氢化锂薄膜沉积速率和表面形貌的影响,采用脉冲激光沉积方法在Si(100)基片上沉积了氢化锂薄膜.通过改变靶基距和氢压等手段来控制薄膜的沉积速率,得到了氢压与沉积速率和薄膜表面质量的关系.结果表明,随着氢压和靶基距的增加,氢化锂薄膜的沉积速率逐渐下降;适当增加氢压可以降低氢化锂薄膜的表面粗糙度.从薄膜生...     

沉积温度对电子束蒸发沉积ZrO2薄膜性质的影响

摘要ZrO2薄膜样品在不同的沉积温度下用电子束蒸发的方法沉积而成。利用X射线衍射(XRD)仪和原子力显微镜(AFM)检测了ZrO2薄膜的晶体结构和表面形貌，发现室温下沉积ZrO2薄膜样品为非晶结构，随着沉积温度升高．ZrO2薄膜出现明显的结晶现象，在薄膜中同时存在四方相及单斜相。薄膜表现为自由取向生长，晶粒尺寸随沉积温度升高而增大。同时发现薄膜中的残余应力随沉积温度的升高，由张应力状态变为压应力状态，这一变化主要是薄膜结构变化引起的内应力的作用结果。同时讨论了不同沉积温度对ZrO2薄膜光学性质的影响。     

沉积气压对氮化硼薄膜场发射特性的影响

利用等离子体增强脉冲激光沉积系统,在n型Si(100)基底上沉积了不同沉积气压下的纳米BN薄膜,利用红外光谱(FTIR)对BN薄膜进行了表征.通过原子力显微镜(AFM)观察了薄膜的表面形貌.在超高真空(＜5.0×10-7 Pa)情况下测量了薄膜的场致发射特性.实验结果表明,沉积气压对BN薄膜的场发射特性影响很大.BN薄膜的阈值电场随着沉积气压的升高而升高,发射极限电流随着沉积气压的升高而较小,但耐压特性提高.沉积气压为2 Pa时沉积的BN薄膜的场发射的阈值电场最低,为12 V/μm,当电场升高到27 V/μm时,场发射电流密度为140.6 μA/cm2;当沉积气压升高到5 Pa时,阈值电场升高为26 V/μm,当电场升高到59 V/μm时,发射电流密度为187.5 μA/cm2;沉积气压升高到15 Pa时的样品的阈值电场已经高达51 V/μm.所有BN薄膜的F-N曲线都符合F-N理论,表明电子发射是通过隧穿表面势垒完成的.     

脉冲激光沉积工艺参数对生物活性薄膜的影响

脉冲激光沉积是近年来出现的一项制备薄膜的新技术,在制备生物活性薄膜方面显示出独特的优越性。介绍了脉冲激光沉积技术的原理及特点,详细综述了反应气氛、衬底温度、激光波长、能量密度、靶材性能、沉积速率及薄膜厚度等工艺参数对羟基磷灰石及生物玻璃薄膜组织及性能的影响,展望了该项技术的应用前景。     

联氨对化学水浴沉积ZnS薄膜的影响

在A(ZnSO4、SC(NH2)2、NH4OH)和含有联氨的B(ZnSO4、SC(NH2)2、NH4OH、(NH2)2)两种水溶液中采用化学水浴法沉积ZnS薄膜,研究了联氨对薄膜沉积过程和薄膜性质的影响.结果表明,加入少量联氨以后,薄膜沉积速度明显增加.两种溶液沉积的ZnS都为立方相结构,且含有联氨的B溶液沉积的ZnS薄膜表面附着颗粒较少.在含有联氨的B溶液中沉积的ZnS薄膜结晶度和短波区的透过率均高于A溶液沉积的ZnS薄膜.将两种溶液沉积的ZnS薄膜作为电池缓冲层制备铜铟镓硒(CIGS)薄膜太阳电池,加入联氨沉积的ZnS制备的CIGS电池转换效率达到7.77%,比不加联氨沉积的ZnS制备的CIGS电池转换效率提高了1.3%.     

离子束溅射沉积光学薄膜速率分布

本文应用高斯型离子束流强度分布计算了离子束溅射沉积光学薄膜的沉积速率分布,结果表明,沉积速率空间分布偏离余弦分布,峰值位置随溅射离子束入射角改变并受离子束高斯半径的影响。实验结果与之相符。     

The development of biaxial alignment in yttria-stabilized zirconia films fabricated by ion beam assisted deposition

Yttria-stabilized zirconia (YSZ) films were deposited using ion assisted, electron beam deposition (IBAD) on Pyrex, quartz, Hastelloy, and polycrystalline zirconia substrates. Film orientation was studied as a function of IBAD fabrication conditions. Film texture from several populations of biaxially aligned grains has been observed. The ion beam is shown to induce biaxial alignment of all grain orientations. Specifically, grains with (200), (311), and (111) normal to the substrate surface are biaxially aligned. The ion beam induces biaxial alignment at all angles of incidence, not just those corresponding to YSZ channeling directions. The development of (200) biaxial alignment on Pyrex is examined as a function of thickness. Biaxially aligned IBAD YSZ films were deposited on amorphous and polycrystalline substrates without active heating. Biaxial alignment development with IBAD is shown to be consistent with a previously proposed growth and extinction model.     

Optical properties of chemical bath deposited CdS thin films

CdS thin films have been prepared by chemical bath deposition. As-deposited films are cubic and show a sulfur deficiency. From the transmittance and reflectance data analysis direct band gaps (E_g) ranging from 2.180 to 2.448 eV have been obtained. Air and vacuum annealed samples show a decrease in the band gap. The refractive index (n) lies in the range 1.61–2.34. A dependence of band gap on composition has been observed and the possible reasons are discussed.     

TD—LTE双流波束成形探讨

针对TD-LTER9阶段新增加的TM8（双流波束成形）技术,本论文从原理分析上给出TTM8的实现基本原理,以及相较于TM3／TM7等传输模式的优缺点。结合实际测试情况,分析了TM8在现网中的性能,并给出TTM8的应用建议,希望为TD-LTE的建设与应用方面提供一些借鉴。     

非赋形双偏置高性能椭圆波束天线

分析了非赋形双偏置天线产生椭圆波束的机理,将馈源的椭圆波束照射到轮廓线为椭圆形的付反射面上,通过双偏置天线的对称转换原理,主反射面产生椭圆波束.馈源波束由矩形口径的多模喇叭产生,它提供了等化的方向图.给出了馈源及天线的方向图计算公式.实验结果表明,实测方向图基本与理论计算一致.与其他类型的椭圆波束天线相比,本天线加工简单,同时天线效率也较高.     

离子辅助沉积电子束蒸发Si基SiO2薄膜的研究

研究了离子辅助沉积(IBAD)电子束蒸发和传统电子束蒸发两种镀膜方式在Si(100)面基底所镀SiO2光学薄膜的特性。特别是在离子辅助沉积下,分析了不同工艺条件改变对SiO2光学薄膜的光学特性的影响。结果表明,无论表面形貌、折射率均匀性,还是湿度稳定性,离子辅助电子束蒸发都优于传统电子束蒸发的SiO2光学薄膜,在离子辅助沉积条件下,薄膜折射率在40～160℃范围随衬底温度的升高而提高,镀膜时真空度为1.5×10-3 Pa、沉积速率为5nm/s、离子源驱动电压为285.4V、离子源辅助气体分压比PAr∶PO=1∶1时,SiO2光学薄膜的光学特性最好。     

Analysis of Optical properties of nanocrystalline titanium dioxide films

The optical properties of materials can be characterized in terms of the complex refractive index. We developed a simple and efficient method for determining the complex refractive index of nanomaterials that uses the relationship between this parameter and the light spectrum measured for a specimen. The optical properties of nanoparticle and nanotube TiO₂ films were investigated. The results show that the morphology of nano-TiO₂ affects the complex refractive index spectrum and therefore influences light dispersion and absorption of the film. We also simulated the optical energy density distribution within equivalent plane films using complex refractive index data.     

Characterization of Si-N films prepared by reactive ion beam sputtering

Application of silicon-nitride (Si-N) as a passivant in com-pound semiconductor technology requires a low-temperature deposition process to prevent dissociation of the volatile constituents of the semiconductor. With this in mind, an exploratory study of Si-N films prepared at room temperature using low-energy, reactive ion-beam sputtering has been carried out. The electrical and optical characteristics of the films have been studied, and an annealing step is found necessary to reduce the conductivity of the nitride and im-prove the interfacial properties. On leave of absence from the Department of Physics, Kurukshetra University, Kurukshetra-132119, India.     

Electrical properties of rare earth silicides produced by channeled ion beam synthesis

Electrical measurements have been performed on ErSi_1.7, YSi_1.7 and Er_0.5Y_0.5Si_1.7, produced by channeled ion beam synthesis. The results have been compared with thin films of the same rare earth silicides produced by other methods. The room temperature resistivities of the ErSi_1.7, YSi_1.7 and Er_0.5Y_0.5Si_1.7 are 52, 69 and 87 μΩ cm, respectively, significantly higher than the reported values for MBE synthesised layers. The ErSi_1.7 shows evidence of magnetic ordering, but this is not observed in either the YSi_1.7 or the Er_0.5Y_0.5Si_1.7 down to 3 K.     

聚焦离子束系统原理、应用及进展

聚焦离子束纳米加工系统,具有传统加工工具无可比拟的优势而逐渐成为新一代微纳分析、加工的工具在微纳米加工、操纵以及器件的研制等方面具有重要应用.本文介绍了聚焦离子束系统的内部结构和工作原理,探讨了该系统的扩展功能、应用及发展前景.