Over the recent years, there has been an extensive adoption of Machine Learning (ML) in a plethora of real-world applications, ranging from computer vision to data mining and drug discovery. In this paper, we utilize ML to facilitate efficient film fabrication, specifically Atomic Layer Deposition (ALD). In order to make advances in ALD process development, which is utilized to generate thin films, and its subsequent accelerated adoption in industry, it is imperative to understand the underlying atomistic processes. Towards this end, in situ techniques for monitoring film growth, such as Spectroscopic Ellipsometry (SE), have been proposed. However, in situ SE is associated with complex hardware and, hence, is resource intensive. To address these challenges, we propose an ML-based approach to expedite film thickness estimation. The proposed approach has tremendous implications of faster data acquisition, reduced hardware complexity and easier integration of spectroscopic ellipsometry for in situ monitoring of film thickness deposition. Our experimental results involving SE of TiO2 demonstrate that the proposed ML-based approach furnishes promising thickness prediction accuracy results of 88.76% within +/-1.5 nm and 85.14% within +/-0.5 nm intervals. Furthermore, we furnish accuracy results up to 98% at lower thicknesses, which is a significant improvement over existing SE-based analysis, thereby making our solution a viable option for thickness estimation of ultrathin films.
Real-time observation of oxidation and photo-oxidation of rubrene thin films by spectroscopic ellipsometry
我们使用椭圆偏振光谱法，在控制条件下实时跟踪生长在SiO_2上的有机半导体红荧烯的氧化过程。我们推导出复杂的介电函数ε_1 + i ε_2的原始和氧化红荧烯的氧化是伴随着一个显着的变化的光学性质，即吸收。我们观察到，红荧烯的光氧化比没有光照的氧化快几个数量级。通过跟踪不同的吸收带（原始红荧烯在2.5eV和4.0eV左右，氧化红荧烯在4.9eV左右），我们推断所观察到的这些薄膜的光氧化涉及非Fickian扩散机制。
Evidence of valence band perturbations in GaAsN/GaAs(001): A combined variable-angle spectroscopic ellipsometry and modulated photoreflectance investigation
Unveiling the structural, chemical state, and optical band-gap evolution of Ta-doped epitaxial SrTiO3 thin films using first-principles calculations and spectroscopic ellipsometry
Dielectric Tensor of CrSBr from Spectroscopic Imaging Ellipsometry
Institute of Physics, University of Münster（明斯特大学物理研究所）；Department of Inorganic Chemistry, University of Chemistry and Technology Prague（布拉格化工大学无机化学系）；Center for Soft Nanoscience (SoN), University of Münster（明斯特大学软纳米科学中心）
Operando probing of Li-insertion into LiMn$_2$O$_4$ cathodes by spectroscopic ellipsometry
提出了一种基于椭圆偏振光谱技术（SE）的电池电极离子嵌入和荷电状态的非破坏性观测方法。这种技术的潜力，用于执行时间分辨测量的（脱）锂过程的电极材料已被证明使用薄膜尖晶石LiMn $_2$ O $_4$作为锂离子电池的阴极。Li+离子在该材料中的化学扩散率已经由Li插入到膜中的时间演变确定，并且根据这些结果，已经可以将在该材料中观察到的有争议的赝电容行为与该层的纳米结构相关联。这里提出的结果建立了一个新的方法，电池材料和设备的operando表征提供了一个强大的工具，在电化学设备的集合中的离子扩散机制的理解。
Infrared dielectric function, phonon modes and free-charge carrier properties of high-Al-content Al$_x$Ga$_{1-x}$N alloys determined by mid-infrared spectroscopic ellipsometry and optical Hall effect
用中红外椭圆偏振光谱法测量了4H-SiC衬底上一组高质量Si掺杂的Al $_x$ Ga $_{1-x}$ N外延层的声子模参数和各向异性中红外介电函数张量分量。发现$E_1$（TO）模的双模行为和$A_1$（LO）模的单模行为与先前的拉曼散射光谱报告一致。建立了红外活性声子频率参数的组成依赖关系，并讨论了可能被无序激活的无声$B_1$模式。利用最佳匹配模型导出的声子模频率和高频介电常数参数，应用Lydanne-Sachs-Teller关系，确定了静态介电常数与$x$的关系。用中红外光学霍尔效应测量方法确定了高Al含量的Al-$_x$-Ga-$_{1-x}$-N合金的有效质量参数及其与成分的关系。此外，还研究了具有相似Si掺杂水平的Al-$_x$-Ga $_{1-x}$ N薄膜的自由电子浓度$N$和迁移率参数$μ$随Al含量$x$的变化关系，并进行了讨论。
Pulsed laser deposition with simultaneous in situ real-time monitoring of optical spectroscopic ellipsometry and reflection high-energy electron diffraction
Optical constants of several multilayer transition metal dichalcogenides measured by spectroscopic ellipsometry in the 300-1700 nm range: high-index, anisotropy, and hyperbolicity
Vacancy defects induced changes in the electronic and optical properties of NiO studied by spectroscopic ellipsometry and first-principles calculations
Free-charge carrier parameters of n-type, p-type and compensated InN:Mg determined by Infrared Spectroscopic Ellipsometry
采用红外椭圆偏振光谱法研究了掺镁InN薄膜的自由载流子特性。比较了两组具有代表性的通过分子束外延生长的具有从$1.2\times10^{17}$ cm $^{-3}$到$8\times10^{20}$ cm $^{-3}$的Mg浓度的极性InN。P-型导电性表示的Mg浓度范围为$1\times10^{18}$ cm $^{-3}$到$9\times10^{19}$ cm $^{-3}$从纵向光学声子等离子体加宽和迁移率参数的Mg浓度的依赖性的系统调查。一个参数化的模型，占的声子-等离子体激元耦合被施加到确定的自由载流子浓度和迁移率参数的掺杂的块状InN层，以及GAN模板和未掺杂的InN缓冲层为每个样品。第二样品组中的自由载流子性质与先前报道的第一样品组的综合分析中确定的结果一致[Schöche等人，J. Appl.Phys.113，013502（2013）]。在第二组中，具有$2.3\times10^{20}$ cm $^{-3}$的Mg浓度的两个样品被识别为具有非常低的电子浓度的补偿n型InN，其适合于进一步研究通常由高电子浓度控制的本征材料性质，即使在未掺杂的InN中。补偿的n型InN样品可以清楚地从类似的等离子体频率的p型导电材料的强烈减少的声子等离子体激元展宽区分。
Electronic localization on the structural inhomogeneities formed due to Bi and Te deficiency in the MBE grown films of AFM topological insulator MnBi2Te4: Evidence from spectroscopic ellipsometry and infrared studies
Reactive pulsed direct current magnetron sputtering deposition of semiconducting yttrium oxide thin film in ultralow oxygen atmosphere: A spectroscopic and structural investigation of growth dynamics
Multimodal Visual Sensing of Temperature and Pressure: From Spectroscopic Readout to Multiple Linear Regression-Enhanced RGB Analysis
Institute of Low Temperature and Structure Research Polish Academy of Sciences（波兰科学院低温结构研究所）；State Key Laboratory of High Pressure and Superhard Materials, College of Physics, Jilin University（吉林大学物理学院高压与超硬材料国家重点实验室）；Departamento de Física, and IUdEA, Universidad de La Laguna（拉帕尔马大学物理系和IUdEA）
