电子束蒸发非晶硅光学薄膜工艺研究

研究了沉积时真空室真空度、基片温度和沉积速率对常用电子束蒸发非晶硅(a-Si)光学薄膜的折射率和消光系数的影响。结果表明,在300~1100nm的波长范围内,真空室真空度、基片温度和沉积速率越高,则所得a-Si薄膜折射率越高,消光系数越大。并将实验结果用于半导体激光器腔面高反镜用a-Si膜镀制,发现在选择初始真空为1E-6×133Pa、基片温度为100℃和沉积速率为0.2nm/s时所得高反镜的光学特性比较好,在808nm处折射率和消光系数分别为3.1和1E-3。     

椭偏仪的研究进展

主要介绍了椭偏仪的测量原理,比较了不同结构的椭偏仪,并根据具体应用需求介绍了椭偏光谱仪、红外椭偏光谱仪、成像椭偏仪和广义椭偏仪,分析了椭偏仪的数据处理过程,最后展望了椭偏仪的发展趋势.     

Development and construction of rotating polarizer analyzer ellipsometer

A detailed mathematical derivation and an experimental characterization of one to two ratio rotating polarizer analyzer ellipsometer (RPAE) are presented. The alignment, calibration, and testing of reference samples are also discussed. The optical properties of some known materials obtained by the proposed ellipsometer will be shown and compared to accepted values. Moreover, the constructed ellipsometer will be tested using two ellipsometry standards with different thicknesses.     

衬底温度对氧化钛薄膜的光学常数影响

采用沈阳CK-3高真空磁控溅射薄膜沉积设备在K9玻璃衬底上分别制备了衬底温度为150℃、200℃和250℃的氧化钛薄膜。XRD分析显示这三种温度制备的薄膜由于制备温度不高均没有明显衍射峰,为非晶薄膜。薄膜的光学常数由德国SENTECH SE 850型光谱型椭偏仪对薄膜测试得到,测试波长为300 nm～800 nm,采用Cauchy模型对测试结果进行拟合。结果发现随着制备衬底温度的增大,薄膜的折射率n和消光系数k都随着增大。在衬底温度从150℃增大到250℃时,薄膜的光学带隙从3.46 eV减小到3.02 eV。     

高校椭偏测厚实验的计算机辅助教学

分析了高校椭偏测厚实验中存在的问题，成功研制出具有教学特点的多功能智能椭偏测厚仪和编制了一套该实验的CAI课，实验表明：椭偏测厚实验的计算机辅助教学效果良好。     

直流磁控溅射制备a-Si:H膜工艺及其在激光器腔面膜上的应用

利用直流(DC)磁控溅射方法制备氢化非晶硅(a-Si∶H)薄膜。研究了氢气流量、溅射源功率对膜的沉积速率、氢含量(CH)以及光学性能的影响。通过傅里叶变换红外(FTIR)吸收光谱计算氢含量,其最大原子数分数为11%。用椭偏仪测量了膜的折射率n和消光系数k,发现a-Si∶H薄膜的k值和n值都随CH的增加而减小。将优化的实验结果用于半导体激光器腔面高反镜的镀制,a-Si∶H薄膜在808 nm波长处的n和k分别为3.2和8×10-3,获得了良好的激光输出特性。     

椭偏测厚仪确定薄膜真实厚度的分析

用椭偏测厚仪可以测量薄膜一个周期内的厚度和折射率.本文从理论上分析了采用变入射角确定薄膜的真实厚度时,存在最大可测厚度周期数和最大可测薄膜真实厚度,同时用图形形象描述了周期数、厚度周期、一个周期内的厚度、真实厚度之间的关系及它们与入射角的关系.     

Effect of balanced and unbalanced magnetron sputtering processes on the properties of SnO2 thin films

A comparative study has been carried on the role of balanced magnetron (BM) and unbalanced magnetron (UBM) sputtering processes on the properties of SnO₂ thin films. The oxygen partial pressure, substrate temperature and deposition pressure were kept 20%, 700 °C and 30 mTorr, respectively and the applied RF power varied in the range of 150–250 W. It is observed that the UBM deposition causes significant effect on the structural, electrical and optical properties of SnO₂ thin films than BM as evidenced by X-ray diffraction, C-V, Spectroscopic Ellipsometer and Photoluminescence measurements. The value of band gap (E_g) of the films deposited at 150 W in UBM is found as E_g = 3.83 eV which is much higher than the value of E_g = 3.69 eV as observed in BM sputtering indicating that UBM sputtering results in good crystalline quality. Further, the C-V measurements of SnO₂ thin films deposited using UBM at high power 250 W show hysteresis with large flat band shift indicating that these thin films can be used for the fabrication of memory device. The observed results have been attributed to different mechanisms which exist simultaneously under unbalanced magnetron sputtering due to ion bombardment of growing SnO₂ thin film by energetic Ar+ ions.     

Relaxation of polymer thin films in isothermal temperature‐jump measurements

The dynamic behavior of thin polymer films is of interest in the fabrication of microelectronics and optoelectronics and in the coatings industry. It is known that polymer relaxation is affected by film thickness and the particular substrate/polymer pair. We previously used a spectroscopic ellipsometer to investigate the glass transition in thin films. In addition to information on the modification of thermal transitions such as the glass‐transition temperature, the speed of data acquisition in an automated, spectroscopic ellipsometer, operated at a single wavelength of 780 nm, allows for the direct observation of the isothermal dimensions of a thin polymer film as a function of time after a rapid temperature change. In this article, we discuss recent results from the observation of the time dependence of film‐normal thickness and normalized, in‐plane, lateral dimension as well as simple fits to this relaxation behavior in terms of a normalized viscosity and relaxation time. The results support a highly asymmetric initial thermal expansion normal to the film followed by close to isotropic relaxation and anisotropic “flow” (the flow in response to the vanishingly small shears of thermal expansion). These features may clarify issues involving the observation of chain confinement in thin polymer films in terms of potential differences between equilibrium and dynamic measurements. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2929–2936, 2000     

基于Labview技术的光度式椭偏测厚仪的研究与设计

本文介绍了一种基于Labview的光度式椭偏仪光学测量系统,用于进行透明薄膜厚度的精确测量.研究并推导出该系统的数学模型及椭偏参数的计算公式.基于C9051F020单片机设计出椭偏仪的控制器并使用Labview编写了测量软件.在测量软件中嵌入Matlab Script节点,完成复杂运算.通过对SiO2薄膜的测试,验证了仪器具有良好的可靠性和重复性,薄膜厚度误差小于100 A,折射率误差小于0.01.