Geometric analysis algorithm based on a neural network with localized simulation data for nano-grating structure using Mueller matrix spectroscopic ellipsometry.

Mueller matrix spectroscopic ellipsometry (MMSE) is a nondestructive tool for nanostructure analysis, and recently the enhanced computational power, combining neural networks and simulation data, enhance its analysis ability on more complex geometries. This study introduces a deep learning method to realize fast and accurate analysis; predicting nanostructure parameters by pairing Mueller matrices with relatively limited library data and then applying neural network algorithm. Thus, it was realized to predict the width and height of 1D grating structure with an accuracy of MAE below 0.

Robust dynamic spectroscopic imaging ellipsometer based on a monolithic polarizing Linnik interferometer.

We describe a robust dynamic spectroscopic imaging ellipsometer (DSIE) based on a monolithic Linnik-type polarizing interferometer. The Linnik-type monolithic scheme combined with an additional compensation channel solves the long-term stability problem of previous single-channel DSIE. The importance of a global mapping phase error compensation method is also addressed for accurate 3-D cubic spectroscopic ellipsometric mapping in large-scale applications.

Measurement uncertainty evaluation procedures and applications for various types of multichannel rotating-element spectroscopic ellipsometers.

A universal measurement uncertainty evaluation procedure is required for different types of multichannel rotating-element spectroscopic ellipsometers (RE-SEs) used in modern semiconductor industry. Herein, an improved uncertainty evaluation procedure, based on the universal measurement model functions and implicit function theorem, is introduced for unknown optical parameters of a sample. In addition, we develop a measurement standard instrument that can solve the error problems related to the basic principles of the multichannel RE-SEs used in the industrial field and present an example of applying the proposed uncertainty evaluation method to this standard instrument.

Normal-incidence type solution immersed silicon (SIS) biosensor for ultra-sensitive, label-free detection of cardiac troponin I.

Early diagnosis of acute myocardial infarction (AMI) significantly reduce the mortality rate and can be achieved via high-sensitive detection of AMI specific cardiac troponin I (cTnI) biomarker. Here, we present normal-incident type solution-immersed silicon (NI-SIS) ellipsometric biosensor, designed for ultra-high sensitive, high-throughput, label-free detection of the target protein. The NI-SIS sensors are equipped with a specially designed prism that maintains the angle of incidence close to the Brewster angle during operation, which significantly reduces SIS noise signals induced by the refractive index fluctuations of the surrounding medium, improves the signal-to-noise ratio, in-results lowers the detection limit.

Interferometric snapshot spectro-ellipsometry.

We propose a snapshot spectroscopic ellipsometry and its applications for real-time thin-film thickness measurement. The proposed system employs an interferometric polarization-modulation module that can measure the spectroscopic ellipsometric phase for thin-film deposited on a substrate with a measurement speed of around 20 msec. It requires neither moving parts nor time dependent modulation devices.

Wafer-scale production of highly uniform two-dimensional MoS by metal-organic chemical vapor deposition.

Semiconducting two-dimensional (2D) materials, particularly extremely thin molybdenum disulfide (MoS) films, are attracting considerable attention from academia and industry owing to their distinctive optical and electrical properties. Here, we present the direct growth of a MoS monolayer with unprecedented spatial and structural uniformity across an entire 8 inch SiO/Si wafer. The influences of growth pressure, ambient gases (Ar, H), and S/Mo molar flow ratio on the MoS layered growth were explored by considering the domain size, nucleation sites, morphology, and impurity incorporation.

Label-free detection of hepatitis B virus using solution immersed silicon sensors.

Highly sensitive solution immersed silicon (SIS) biosensors were developed for detection of hepatitis B virus (HBV) infection in the early stage. The ultrasensitivity for overlayer thickness at the nonreflecting condition for the p-polarized wave is the basis of SIS sensing technology. The change in thickness due to biomolecular interactions and change in refractive index of the surrounding buffer medium were assessed simultaneously using two separate ellipsometric parameters (Ψ and Δ), respectively, from a single sensing spot.

Universal evaluation of combined standard uncertainty for rotating-element spectroscopic ellipsometers.

We present for the first time a universal expression for the combined standard uncertainty for all types of rotating-element spectroscopic ellipsometers (RE-SEs). Specifically, we introduce general model functions as universal analytic expressions for the combined standard uncertainties of the ellipsometric sample parameters. The model functions are expressed as functions of influencing quantities that are not known exactly.

Ultrasensitive, label-free detection of cardiac biomarkers with optical SIS sensor.

Acute myocardial infarction (MI) is the leading cause of high mortality and morbidity rate worldwide, early and accurate diagnosis can increase the chances of survival. In this work, we report a simple, ultrasensitive, label-free, and high-throughput solution immersed silicon (SIS) immunosensor based on non-reflection condition (NRC) for p-polarized wave for early diagnosis of MI. SIS sensor chips are just a thin dielectric polymer layer on the silicon surface, which can be functionalized for specific application.

Universal evaluations and expressions of measuring uncertainty for rotating-element spectroscopic ellipsometers.

We obtain the universal evaluations and expressions of measuring uncertainty for all types of rotating-element spectroscopic ellipsometers. We introduce a general data-reduction process to represent the universal analytic functions of the combined standard uncertainties of the ellipsometric sample parameters. To solve the incompleteness of the analytic expressions, we formulate the estimated covariance for the Fourier coefficient means extracted from the radiant flux waveform using a new Fourier analysis.

Stokes vector measurement based on snapshot polarization-sensitive spectral interferometry.

This paper describes a Stokes vector measurement method based on a snapshot polarization-sensitive spectral interferometry. We measure perpendicular linearly polarized complex wave information of an anisotropic object in the spectral domain from which an accurate Stokes vector can be extracted. The proposed Stokes vector measurement method is robust to the object plane 3-D pose variation and external noise, and it provides a reliable snapshot solution in numerous spectral polarization-related applications.

Optimizing the precision of a multichannel three-polarizer spectroscopic ellipsometer.

We developed a multichannel three-polarizer spectroscopic ellipsometer based on a data acquisition algorithm for achieving optimized precision. This algorithm measures unnormalized Fourier coefficients accurately and precisely. Offset angles for optical elements were obtained as wavelength-independent values using regression calibration.

Calibration of a snapshot phase-resolved polarization-sensitive spectral reflectometer.

This Letter describes a universal calibration theory by which conventional interferometry can be extended to vibration robust snapshot polarization-sensitive spectral reflectometry without any complicated optical components or active devices. Experiments for verifying the proposed calibration theory have been conducted by using a Michelson-interferometer-based normal incidence spectroellipsometric system, and also some key system design considerations for object 3D pose tolerant measurement capability have been drawn. The proposed solution enables us to extract the spectroscopic ellipsometric parameter Δ(k) of an anisotropic object within 10 ms with high accuracy.

Complex object wave direct extraction method in off-axis digital holography.

Off-axis digital holography generally uses a 2D-FFT based spatial filtering method to extract the complex object wave from an off-axis hologram. In this paper, we describe a novel single exposure complex object wave extraction method which can provide a faster solution than the FFT based spatial filtering approach while maintaining the reconstructed phase image quality. And also, we show that the proposed direct filtering scheme can provide more robust filtering capability to the off-axis spatial carrier frequency variation than the spatial filtering method.

Snapshot phase sensitive scatterometry based on double-channel spectral carrier frequency concept.

Spectroscopic ellipsometry is one of the most important measurement schemes used in the optical nano-metrology for not only thin film measurement but also nano pattern 3D structure measurement. In this paper, we propose a novel snap shot phase sensitive normal incidence spectroscopic ellipsometic scheme based on a double-channel spectral carrier frequency concept. The proposed method can provide both Ψ(λ) and Δ(λ) only by using two spectra acquired simultaneously through the double spectroscopic channels.

Study of cell-matrix adhesion dynamics using surface plasmon resonance imaging ellipsometry.

The interaction of cells with extracellular matrix, termed cell-matrix adhesions, importantly governs multiple cellular phenomena. Knowledge of the functional dynamics of cell-matrix adhesion could provide critical clues for understanding biological phenomena. We developed surface plasmon resonance imaging ellipsometry (SPRIE) to provide high contrast images of the cell-matrix interface in unlabeled living cells.

Fourier analysis for rotating-element ellipsometers.

We introduce a Fourier analysis of the waveform of periodic light-irradiance variation to capture Fourier coefficients for multichannel rotating-element ellipsometers. In this analysis, the Fourier coefficients for a sample are obtained using a discrete Fourier transform on the exposures. The analysis gives a generic function that encompasses the discrete Fourier transform or the Hadamard transform, depending on the specific conditions.

Long-term stability of cell micropatterns on poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide)-patterned silicon oxide surfaces.

In this work, we compared the long-term stability and integrity of cell patterns on newly reported, zwitterionic poly((3-(methacryloylamino)propyl)dimethyl(3-sulfopropyl)ammonium hydroxide) (poly(MPDSAH)) films with those on widely used, poly(poly(ethylene glycol) methyl ether methacrylate) (poly(PEGMEMA)) ones. The micropatterns of both polymers were formed on a silicon oxide surface by a combination of micropattern generation of a photoresist, vapor deposition of a silane-based polymerization initiator, and surface-initiated, atom transfer radical polymerization (SI-ATRP) of each monomer, MPDSAH or PEGMEMA. The successful formation of the silane initiator SAMs, and poly(MPDSAH) and poly(PEGMEMA) micropatterns was confirmed by X-ray photoelectron spectroscopy (XPS) and imaging ellipsometry.

Angle-resolved annular data acquisition method for microellipsometry.

An ellipsometric data acquisition method is introduced to measure the optical properties of sample. It is based on a microellipsometer hardware layout integrated a high numerical aperture objective lens, which is aligned in the normal direction of sample surface. This technique enables to achieve ellipsometric data at multiple incident angle with a sub-mum probe beam size, moreover real-time measurement is possible due to no moving parts.