SnTe纳米薄膜的椭圆偏振光谱研究

SnTe纳米薄膜材料光学常数的准确获取，对于其在高性能光电器件设计和在光电子领域的潜在应用具有重要的意义。然而，目前仍然很少有关于获取其纳米薄膜光学常数方法的相关研究报道。采用磁控溅射法以SnTe单靶为靶材，在石英衬底上制备了SnTe纳米薄膜；在未加衬底温度和未进行退火处理的条件下，通过制备工艺参数优化，即得到晶化的、组分可控的面心立方结构SnTe纳米薄膜。采用椭圆偏振光谱法，建立不同的拟合模型结构，利用SE数据库中的SnTe材料数据列表和Tauc-Laurents模型对所制备的SnTe纳米薄膜材料的膜厚、组成及折射率、消光系数等光学常数进行了研究。结果显示，具有该厚度的SnTe纳米薄膜材料在可见光波段具有较高的折射率、在可见到近红外具有较宽的光谱吸收。     

SiGe薄膜材料的椭圆偏振光谱研究

采用椭圆偏振光谱(SE)对一系列SiGe样品进行了研究。确定了SixGe1-x层的厚度和组分;对不均匀的SixGe1-x层,沿厚度方向进行了组分梯度的研究,其结果与二次离子质谱(SIMS)的测试有较好的一致性;成功地表征了器件级绝缘体上的硅锗(SGOI)样品的各层结构和SixGe1-x层的组分。     

唯一性检测在椭圆偏振光谱薄膜拟合中的应用（英文）

利用椭圆偏振光谱进行薄膜样品的测量数据分析拟合时,薄膜厚度与介电常数通常具有一定的关联性.不同色散模型的选取也会对拟合结果产生明显的影响,引起较大误差.介绍了唯一性检测在椭偏拟合中的实现方法.并以二氧化钛样品为例,利用唯一性检测对比了不同色散模型、不同厚度、不同测量波段、不同入射角度时的唯一性检测结果.结果表明,唯一性检测能够有效标定出椭偏测量和拟合过程中所产生的误差,同时能够对不同色散模型进行量化对比,提升拟合精度.     

GaN折射率的椭圆偏振光谱研究

利用400～1200nm波段的椭圆偏振光谱对生长在蓝宝石衬底上的非故意掺杂纤锌矿氮化镓(GaN)外延薄膜进行了研究．通过拟合实验数据获得了GaN薄膜的厚度和在可见-近红外区域的折射率色散关系,即n^2(A)=2．26^2 330．1^2／((λ／nm)^2-265．7^2)．利用这一公式研究了GaN紫外-可见波段的反射光谱,计算得到的GaN薄膜厚度,与椭偏光谱结果一致,两者偏差仅为0．68％．     

PbZr0.52Ti0.48O3薄膜红外椭圆偏振光谱研究

用磁控溅射法在Pt/Ti/SiO2 /Si衬底上制备了PbZr0 .52 Ti0 .4 8O3(PZT)薄膜 .XRD结果表明经过退火后的PZT薄膜呈现多晶结构 .通过红外椭圆偏振光谱仪测量了λ为 2 .5～ 12 .6 μm范围内PZT薄膜的椭偏光谱 ,采用经典色散模型拟合获得PZT薄膜的红外光学常数 ,同时拟合得到未经处理的PZT薄膜和退火后PZT薄膜的厚度分别为 45 4.2nm和 45 0 .3nm .最后通过拟合计算得到结晶PZT薄膜的静态电荷值为 |q|=1.76 9± 0 .0 2 4.这说明在磁控溅射法制备的PZT薄膜中 ,电荷的转移是不完全的 .     

不同取向金刚石薄膜的红外椭圆偏振光谱特性研究

采用红外椭圆偏振光谱仪对HFCVD方法所制备的不同取向金刚石薄膜的光学参数进行了测量.结果表明(001)取向金刚石薄膜具有较佳的光学质量,在红外波段基本是透明的.在2.5~12.5μm红外波长范围内,(001)取向金刚石膜的折射率和消光系数几乎不随波长的改变而变化,折射率为2.391,消光系数在10-5范围内;对于(111)取向金刚石膜,其折射率和消光系数随波长的改变有微小变化,折射率和消光系数都低于(001)取向膜.通过计算拟合得到(001)取向金刚石膜的介电常数为5.83,优于(111)取向膜.     

非晶态碲镉汞薄膜晶化过程的椭圆偏振光谱研究

采用椭圆偏振光谱技术研究了非晶态碲镉汞薄膜在不同退火条件下的结构性能.结果表明非晶态碲镉汞薄膜在退火过程中的成核晶化是在薄膜内部均匀发生的,对于不同晶化程度的薄膜,其光学常数谱具有明显的特征,通过对光学常数谱的分析研究可以对非晶态碲镉汞薄膜的晶化程度进行量化表征,从而控制退火条件,优化材料质量.     

GaAs体材料折射率红外椭圆偏振光谱研究

报道了采用红外椭圆偏振光谱术测量ＧａＡｓ体材料折射率,测量范围为２．５～１２．５μｍ,并将所得实验数据与理论计算和其它实验结果进行了对比,表明了实验结果的可靠性．     

用椭圆偏振光谱精确确定半导体材料临界点的位置

分析了波长调制反射谱，实际是介电函数对能量的一级微商。导出了弱电场调制反射谱与介电函数对能量的三级微商成正比，将ＭＯＣＶＤ方法生长的ＧａＩｎＰ以及掺Ｓｉ和掺Ｚｎ三个样品，用椭偏光谱法测量得以可见光区的介电函数谱，求其一级和三级微商谱，将用于分析电反射谱的三点法推广用于分析介电函数的一级和三级微商谱，得到波长调制和弱电场调制反射谱的实验结果，并与介电函数谱的结果加以比较，使灵敏度和分辨率有很大提高。     

红外椭圆偏振光谱研究GaxIn1—xAsySb1—y材料的禁带宽度

采用红外椭辰我谱研究了与ＧａＳｂ衬底近晶格匹配的不同组分ＧａｘＩｎ１－ｘＡｓｙＳｂ１－ｙ样品位于禁带宽度能量位置之上、附近和之下的室温折射率光谱。根据禁带宽度能量位置附近的折射率增强效率确定了ＧａｘＩｎ１－ｘＡｓｙＳｂ１－ｙ样品的禁带宽度,并发现在组分ｘ＝０．２￣０．３之间禁带宽度随组分ｘ近似于线性变化。     

基于原位共角椭偏与反射谱的TiO2薄膜光学常数分析

为了分析溶胶-凝胶法制备的TiO₂薄膜的光学常数,采用旋涂法制备了多层TiO₂薄膜,利用扫描电镜对表面形貌进行了分析,利用椭圆偏振光谱对薄膜的折射率色散和孔隙率进行了拟合分析,并利用原位共角反射光谱对拟合结果进行了验证,得到了TiO₂薄膜厚度、孔隙率和折射率色散曲线。结果表明,TiO₂薄膜厚度与旋涂层数成线性关系,薄膜孔隙率约为15%且与旋涂层数无关,New Amorphous色散模型可以较好地拟合溶胶-凝胶旋涂方法制备的TiO₂薄膜在1.55eV~4.00eV波段的椭偏光谱。该研究为溶胶-凝胶法制备的TiO₂薄膜的光学常数测量提供了参考。     

Through‐the‐glass spectroscopic ellipsometry for analysis of CdTe thin‐film solar cells in the superstrate configuration

Polycrystalline CdS/CdTe thin‐film solar cells in the superstrate configuration have been studied by spectroscopic ellipsometry (SE) using glass side illumination. In this measurement method, the first reflection from the ambient/glass interface is rejected, whereas the second reflection from the glass/film‐stack interface is collected; higher order reflections are also rejected. The SE analysis incorporates parameterized dielectric functions ε for solar cell component materials obtained by in situ and variable‐angle SE. In the SE analysis of the complete cells, a step‐wise procedure ranks the fitting parameters, including thicknesses and those defining the spectra in ε, according to their ability to reduce the root‐mean‐square deviation between the simulated and measured SE spectra. The best fit thicknesses from this analysis are found to be consistent with electron microscopy. Based on the SE results, the solar cell quantum efficiency (QE) can be simulated without any free parameters, and comparisons with measured QE enable optical model refinements as well as identification of optical and electronic losses. These capabilities have wide applications in photovoltaic module mapping and in‐line monitoring. Copyright © 2016 John Wiley & Sons, Ltd.     

不同制备工艺下氧化硅和氧化铪薄膜的椭偏光谱

椭偏技术是一种分析表面的光学方法,通过测量被测对象(样品)反射出的光线的偏振状态的变化情况来研究被测物质的性质。结合XRD和原子力显微镜等方法,利用椭圆偏振光谱仪测试了单层SiO2薄膜(K9基片)和单层HfO2薄膜(K9基片)的椭偏参数,并用Sellmeier模型和Cauchy模型对两种薄膜进行拟合,获得了SiO2薄膜和HfO2薄膜在300～800 nm波段内的色散关系。用X射线衍射仪确定薄膜结构,用原子力显微镜观察薄膜的微观形貌,分析表明:SiO2薄膜晶相结构呈现无定型结构,HfO2薄膜的晶相结构呈现单斜相结构;薄膜光学常数的大小和薄膜的表面形貌有关;Sellmeier和Cauchy模型较好地描述了该波段内薄膜的光学性能,并得到薄膜的折射率和消光系数等光学常数随波长的变化规律。     

利用椭偏仪研究氢气退火处理对ZnO-Ga薄膜光学性能的影响

通过溶胶凝胶技术制备了不同Ga掺杂含量的ZnO透明导电薄膜,研究了Ga掺杂对GZO薄膜结构、电学及光学性能的影响.从X射线衍射光谱分析,所有薄膜均表现为六方纤锌矿结构,经过氢气退火处理之后,薄膜的电学性能均得到提高,当Ga掺杂含量为5 at%时,得到薄膜的电阻率为3.410×10-3 Ω·cm.利用可变入射角椭圆偏振光谱仪(VASE)在270~1 600 nm波长范围内研究了GZO薄膜折射率和消光系数的变化,采用双振子模型对实验数据进行拟合.     

In-situ spectroscopic ellipsometry of HgCdTe

An in-situ spectroscopic ellipsometer has been equipped on a molecular beam epitaxy system to improve control of HgCdTe growth. Using this device, in-situ analysis of composition, growth rate, and surface cleanliness were monitored. A real time model which determined the compositional profile was used. The ellipsometer was employed to give in-situ real time control of the growth process.     

椭圆偏振研究溅射气压对锰膜光学性质的影响

采用射频磁控溅射技术在Si(111)基片上制备金属锰膜,用椭圆偏振光谱在2.0~4.0 e V光子能量范围内研究了溅射压强对锰膜光学性质的影响.分别用德鲁得-洛伦兹模型以及有效介质模型对椭偏参数进行拟合,结果表明随压强增大薄膜致密度先增大后减少;折射率随压强增大先减少后增大;而消光系数随压强的变化与光子能量有关,在低能量区变化复杂,高能量区随压强增加与折射率规律一致.分析表明上述变化与薄膜的致密度密切相关.     

Composition control of long wavelength MBE HgCdTe using In-situ spectroscopic ellipsometry

Improved composition control of Hg_1-xCd_xTe layers grown by molecular beam epitaxy using in-situ spectroscopic ellipsometry is described. This has increased our composition yields from <40% to approximately 70% for a specification of x to within 0.0015 of target composition. Knowledge of composition during growth also enables corrections to effusion cell temperatures so that the in-depth composition profile can be controlled. Further improvements were obtained after active composition control was implemented whereby the ellipsometer controls the Te cell temperature to maintain the desired composition.     

Optical properties of InN studied by spectroscopic ellipsometry

With recently developed InN epitaxy via a controlling In bilayer, spectroscopic ellipsometry (SE) measurements had been carried out on the grown InN and the measured ellipsometric spectra were fitted with the Delta Psi2 software by using a suitable model and the dispersion rule. The thickness was measured by a scanning electron microscope (SEM). Insight into the film quality of InN and the lattice constant were gained by X-ray diffraction (XRD). By fitting the SE, the thickness of the InN film is consistent with that obtained by SEM cross-sectional thickness measurement. The optical bandgap of InN was put forward to be 1.05 eV, which conforms to the experimental results measured by the absorption spectrum and cathodoluminescence (CL). The refractive index and the extinction coefficient of interest were represented for InN, which is useful to design optoelectronic devices.     

GaN外延膜的红外椭偏光谱研究

利用红外椭偏光谱法（IRSE）对生长在蓝宝石衬底上的非故意掺杂的GaN外延膜进行了研究。通过对椭偏光谱的理论计算，拟合了本征GaN中的声子振动参量和等离子振荡的频率及阻尼常量，并由此得到了各向异性的折射率和消光系数的色散曲线以及载流子浓度和迁移率。将得到的电学参数同霍耳测量结果进行了比较。     

Low-k dielectrics: a non-destructive characterization by infrared spectroscopic ellipsometry

An infrared spectroscopic ellipsometer devoted to the characterization of silicon microelectronics has recently been developed at SOPRA. Its main feature is the ability to measure on a small spot (80×200 μm) with a high signal/noise ratio. An original patented optical design suppresses back face reflection and ensures good-quality spectral measurements in the 600–7000 cm⁻¹ range. The excellent signal/noise ratio allows the performance of measurements in less than 30 s. Automation and real-time analysis are included to offer an operator-orientated metrology tool. Details of the instrument are presented, and its use for the characterization of different kinds of low-k dielectrics.