Polishing Grit Research Articles

Surface roughness characterization using representative elementary area (REA) analysis

We proposed the Representative Elementary Area (REA) analysis method and illustrated how it is needed to evaluate representative roughness parameters of surfaces. We used mean height (Sa) roughness to study how its variations converge to a steady state as we expanded the area of investigation (AOI) using combined scan tiles obtained through Confocal Laser Scanning Microscopy. We tested quartz and glass surfaces, subjecting them to various levels of polishing with grit sizes ranging between # 60 and #1200. The scan tiles revealed a multiscale roughness texture characterized by the dominance of valleys over peaks, lacking a fractal nature. REA analysis revealed Sa variations converged to a steady state as AOI increased, highlighting the necessity of the proposed method. The steady-state Sa, denoted as SaREA\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{Sa}}}_{{\ ext{REA}}}$$\\end{document}, followed an inverse power law with polishing grit size, with its exponent dependent on the material hardness. The REA length representing SaREA\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{Sa}}}_{{\ ext{REA}}}$$\\end{document} of glass surfaces, followed another inverse power law with polishing grit size and an indeterminate relationship for quartz surfaces. The multiscale characteristics and convergence to steady state were also evident in skewness, kurtosis, and autocorrelation length (Sal) parameters. Sal increased to a maximum value before decreasing linearly as AOI was linearly increased. The maximum Sal, termed as Salmax\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{Sal}}}_{{\ ext{max}}}$$\\end{document}, exhibited a linear relationship with REA. In the absence of REA analysis, the magnitude of uncertainty depended on the polishing grit size. Finely polished surfaces exhibited a 10–20% variability, which increased to up to 70% relative to the steady-state Sa with coarser polishing.

Influence of Surface Roughness on Nanocrystalline Diamond Films Deposited by Distributed Antenna Array Microwave System on TA6V Substrates

In this study, the characteristics of nanocrystalline diamond films synthesized at low surface temperature on Ti-6Al-4V (TA6V) substrates using a distributed antenna array microwave reactor aiming at biomedical applications were investigated. The surface roughness of the TA6V substrates is varied by scratching with emery paper of 1200, 2400, 4000 polishing grit. Nanocrystalline diamond (NCD) coatings with morphology, purity, and microstructure comparable to those obtained on silicon substrates usually employed in the same reactor and growth conditions are successfully achieved whatever the polishing protocol. However, the latter has a significant effect on the roughness parameters and hardness of the NCD films. The use of the finest polishing grit thus permits us to enhance the hardness value, which can be related to the work-hardening phenomenon arising from the polishing process.

Defects and the Formation of Impurity ‘Hot Spots’ in HgCdTe/CdZnTe

The formation of impurity ‘hot spot’ macro-defects—localized high impurity level contaminates—is examined. The evolution of macro-defects through their critical stages: as-received CdZnTe substrate, molecular beam epitaxy (MBE) prep etch, Te/oxide desorption and stabilization at deposition temp in MBE chamber, thin (200 nm) HgCdTe deposition, and thick (> 4 μm) MBE HgCdTe deposition, is analyzed. As-received CdZnTe wafers have small and large agglomerations of residual SiO2 and Al2O3 polishing grit. Additionally, macro-defects composed of organic residue, Cd(Zn)Te particulates, and additional impurities are also observed. The MBE preparation etch does not significantly alter the types of defects found on the wafer. The Te/oxide desorption process adds a small number of defects due to colloidal graphite particles. HgCdTe deposition introduces MBE spit defects and Hg droplet residue. There is significant movement of polishing grit and organic macro-defects during the various processing steps. Energy dispersive X-ray spectroscopy (EDS) analysis of MBE spit defects shows they are Cd rich with some of the spit defects containing high concentrations of impurities. The vertical gradient in Te concentration associated with the overgrowth on a metal rich MBE spit defect acts as an impurity pipe for Cu to travel toward the surface to become a ‘hot spot’ defect.

Characterization of (111)B and (211)B CdZnTe Substrates for HgCdTe Growth

We have studied state-of-the-art CdZnTe (211)B and (111)B substrates and compared them to each other and to substrates from an alternative vendor. The CdZnTe surface has been characterized both as-received and after growth preparation procedures using dark field optical microscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy, atomic force microscopy, Fourier transform infrared transmission spectroscopy, and secondary ion mass spectroscopy. From these measurements we have obtained densities of particles and morphological defects with size > 0.5 μm, densities of small particles/features with size ≤ 100 nm, and substrate/film interface impurities. The state-of-the-art substrates all have remains of silica grit polishing particles around the edges. The as-received (111)B substrates had very few particles or morphological defects on the surface, but a Br:methanol surface preparation etch exposed a large number of features with sizes ≤ 100 nm. Some of these were silica grit particles, but most of them were Te precipitates. The (111)B substrate from an alternative vendor had a lot of different particles, stains, and voids. It improved significantly after a fine-polishing procedure, but still had the surface with most defects after surface preparation. The state-of-the-art (211)B had the largest as-received density of small features, but after Br:methanol etching this density (of Te precipitates and silica grit particles) was the same as for the etched (111)B substrate. SIMS measurements showed that some of the polishing grit particles ended up on the top surface after surface preparation. Hydrofluoric acid can be used to etch away the silica particles.

Analysis of Etched CdZnTe Substrates

State-of-the-art as-received (112)B CdZnTe substrates have been examined for surface impurity contamination and polishing residue. Two 4 cm × 4 cm and one 6 cm × 6 cm (112)B state-of-the-art as-received CdZnTe wafers were analyzed. A maximum surface impurity concentration of Al = 1.7 × 1015 atoms cm−2, Si = 3.7 × 1013 atoms cm−2, Cl = 3.12 × 1015 atoms cm−2, S = 1.7 × 1014 atoms cm−2, P = 1.1 × 1014 atoms cm−2, Fe = 1.0 × 1013 atoms cm−2, Br = 1.2 × 1014 atoms cm−2, and Cu = 4 × 1012 atoms cm−2 was observed on the as-received CdZnTe wafers. CdZnTe particulates and residual SiO2 polishing grit were observed on the surface of the as-received (112)B CdZnTe substrates. The polishing grit/CdZnTe particulate density on CdZnTe wafers was observed to vary across a 6 cm × 6 cm wafer from ∼4 × 107 cm−2 to 2.5 × 108 cm−2. The surface impurity and damage layer of the (112)B CdZnTe wafers dictate that a molecular beam epitaxy (MBE) preparation etch is required. The contamination for one 4 cm × 4 cm and one 6 cm × 6 cm CdZnTe wafer after a standard MBE Br:methanol preparation etch procedure was also analyzed. A maximum surface impurity concentration of Al = 2.4 × 1015 atoms cm−2, Si = 4.0 × 1013 atoms cm−2, Cl = 7.5 × 1013 atoms cm−2, S = 4.4 × 1013 atoms cm−2, P = 9.8 × 1013 atoms cm−2, Fe = 1.0 × 1013 atoms cm−2, Br = 2.9 × 1014 atoms cm−2, and Cu = 5.2 × 1012 atoms cm−2 was observed on the MBE preparation-etched CdZnTe wafers. The MBE preparation-etched surface contamination consists of Cd(Zn)Te particles/flakes. No residual SiO2 polishing grit was observed on the (112)B surface.

As-Received CdZnTe Substrate Contamination

State-of-the-art as-received (112)B CdZnTe substrates were examined for surface impurity contamination, polishing damage, and tellurium precipitates/inclusions. A maximum surface impurity concentration of Al = 7.5 × 1014, Si = 3.7 × 1013, Cl = 3.12 × 1015, S = 1.7 × 1014, P = 7.1 × 1013, Fe = 1.0 × 1013, Br = 1.9 × 1012, and Cu = 4 × 1012 atoms cm−2 was observed on an as-received 6 × 6 cm wafer. As-received CdZnTe substrates have scratches and residual polishing grit on the (112)B surface. Polishing scratches are 0.3 nm in depth and 0.1 μm wide. The polishing grit density was observed to vary from wafer-to-wafer from ∼5 × 106 to 2 × 108 cm−2. Te precipitate/inclusion size and density was determined by near-infrared automated microscopy. A Te precipitate/inclusion diameter histogram was obtained for the near-surface (top ~140 μm) of a 6 × 6 cm substrate. The average areal Te precipitate/inclusion density was observed to be fairly uniform. However, there was a large density of Te precipitates/inclusions with a diameter significantly greater than the mean. Te precipitate/inclusion density >10 μm diameter = 2.8 × 103 cm−3. The large Te precipitates/inclusions are laterally non-uniformly distributed across the wafer.

12.5‐Gb/s Highly Flexible 180° Polymer Waveguide on Optical and Electronic Printed Circuit Board

ABSTRACTThe optical interconnection using polymer waveguides on the optical and electronic printed circuit board was designed and fabricated for low optical propagation loss and high speed data rate. The ray tracing simulation for the tolerance study of optical interconnection and fabrication was carried by the LightTools commercial software. In order for the easy fabrication and high position accuracy, the polymer waveguides were forming 45° reflective mirrors using dicing approach and followed by the e‐beam deposition for silver coated 90° beam turning. The interface coupling loss was discussed in different polishing grit sizes and dicing approaches. Upto 12.5 Gb/s transmission rate and 0.1 dB/cm optical propagation loss were demonstrated in the board‐embedded flexible polymer waveguide. The Q factor of 7.4 at 12.5 Gb/s and additional optical loss of 0.3 dB were experimentally shown on the 2‐mm bending radius and 180° curvature angle. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1999–2003, 2013

10 Gb/s Optical Interconnection on Flexible Optical Waveguide in Electronic Printed Circuit Board

In this paper, we proposed 10 Gb/s transmission using 4-channel polymer waveguides on the optical electronic printed circuit board. It was simulated by the ray tracing method for tolerance study of optical interconnection and fabrication. In order for easy fabrication and high position accuracy, the polymer waveguides were forming silver coated 45° reflective mirrors by dicing method and e-beam deposition for 90° light beam turning. The coupling loss was demonstrated in different polishing grit sizes. The optical interconnection in board-embed 4-channel flexible waveguides was demonstrated with a low propagation loss of 0.1 dB/cm and a clear eye diagram at 2.5 Gb/s data rate per channel.

FRD in optical fibres at low temperatures: investigations for Gemini's Wide-field Fibre Multi-Object Spectrograph

While there is no direct evidence for the deterioration in Focal Ratio Degradation (FRD) of optical fibres in severe temperature gradients, the fibre ends inserted into metallic containment devices such as steel ferrules can be a source of stress, and hence increased FRD at low temperatures. In such conditions, instruments using optical fibres may suffer some increase in FRD and consequent loss of system throughput when they are working in environments with significant thermal gradients, a common characteristic of ground-based observatories. In this paper we present results of experiments with optical fibres inserted in different materials as a part of our prototyping study for Gemini's Wide-field Multi-Object Spectrograph (WFMOS) project. Thermal effects and the use of new holding techniques will be discussed in the context of Integral Field Units and multi-fibres systems. In this work, we have used careful methodologies that give absolute measurements of FRD to quantify the advantages of using epoxy-based composites rather than metals as support structures for the fibre ends. This is shown to be especially important in minimizing thermally induced stresses in the fibre terminations. Not only is this important for optimizing fibre spectrograph performance but the benefits of using such materials are demonstrated in the minimization of positional variations and the avoidance of metal-to-glass delamination. Furthermore, by impregnating the composites with small zirconium oxide particles the composite materials supply their own fine polishing grit which aids significantly to the optical quality of the finished product.

Methods for reducing stress birefringence in cadmium telluride electro-optic modulators

By studying the static birefringence pattern of cadmium telluride electro-optic modulator crystals after fabrication, it has been determined that standard fabrication processes induce excessive stress birefringence. This stress birefringence is produced during the grinding stage of fabrication. Two methods for removing this birefringence have been explored: (1) mechanical polishing of the sides of the crystal to an optical finish, and (2) chemical etching of the sides of the crystal with a 5% bromine solution. Both methods reduced the static birefringence of the crystal. The stress birefringence pattern can be recreated by grinding the sides of the crystal with 9 μm polishing grit.

Surface modification of the PLT lower hybrid waveguides to improve operations

Arrays of waveguides for use in PLT during lower hybrid wave heating and current drive experiments have been treated to improve resistance to high power rf breakdown. The breakdown, which even after extensive conditioning of stainless steel waveguides occurs at power levels of ≳1 kW/cm2, has been attributed to gas evolved from waveguide walls, electron multipacting, photoelectron emission and/or arcing. A waveguide treatment program has been developed to reduce each of these effects. Mechanical polishing of the waveguide, by means of a unique polishing jig, removes surface protrusions of ?0.001 in. Electrochemical polishing is then used to remove imbedded polishing grit and reduce surface roughness, thereby reducing the surface area for adsorbed gases. Ultrasonic cleaning in hot Alconox removes the residue. The interior of the waveguide array is then coated with glyptal or by electrophoretic deposition of carbon lamp black suspended in a glyptal/xylene solution. The resultant 1–5‐μ‐thick film is vacuum py...

Ion Polishing of Metal Surfaces

Various combinations of ion polishing and vacuum annealing were used in an attempt to reduce the optical absorptance and to smooth the surfaces of polycrystalline metal mirrors for high power lasers. The samples included micromachined copper and conventionally polished copper and molybdenum mirrors. It was found that ion polishing and vacuum annealing resulted in a large decrease, 40 to 50%, in the absorptance at 10.6 pm for conventionally polished copper samples and a small decrease, 5 to 10%, in the absorptance of micromachined copper and conventionally polished molybdenum mirrors. After ion polishing and annealing, the absorptance of the conventionally polished copper mirrors was as low as that of the micromachined mirrors. Ion polishing proved beneficial in removing surface defects, such as machining marks, scratches, and embedded polishing grit, and oxide layers; however, for large amounts of material removed, differential sputtering of the various crystallites led to grain boundary delineation and surface roughening. Thus, there exists an optimum amount of material to be removed by ion polishing which results in both maximum removal of surface defects and minimum roughening of the surface. The optimum amounts were found to be: 2500 to 5000 A for micromachined copper, 5000 to 7000 A for conventionally polished copper, and less than 1500 A for molybdenum.

Two-Magnon Linewidth Induced by Multipole Demagnetizations of Surface Imperfections on Zn2Y

On single crystal Zn 2 Y , the experimental linewidth induced by surface imperfections is compared with the theoretical one. The theoretical calculation is made in consideration of dipole and quadrupole demagnetizations of the imperfections and with the use of the effective exchange constants D ⊥ =0.15×10 -9 Oe cm 2 and D // =9.3×10 -9 Oe cm 2 within and between the crystallographic c planes. The experimental linewidth agrees well with this calculation rather than the other two results calculated by Sparks-Loudon-Kittel and Seiden-Sparks methods. The ratio of the quadrupole contribution to the dipole increases with decrease of polishing grit size. The extended calculation for the higher order multipoles than the quadrupole achieves the more precise approach of the calculated linewidth to the experimental one.

18-8ステンレス鋼のエメリー研摩

The conditions of polishing of 18-8 stainless steel have mainly relied upon experimentations. There have been no definite values as to the force exerted in polishing. As the results, too strong force caused overheating, or too weak force could not remove imperfections from the surface.The object of the authors' study was to technically determine the exerting force on emery cloth and polishing compounds of grease-base which are used in manufacturing table and kitchen wares in Japan.The polishing wheel used in this experiment was made of canvas; its diameter was 1.1 in., its peripheral speed was 6, 000-7, 000ft./min., and its grain size of polishing grit was #180.The following results were obtained.1. When the force of 7.1lb./in2 was exerted in dry polishing, polishing burn was caused; but the burn was not caused for the force of 24lb/in2 when tripolite was used as lubricating abrasives.The depth of polishing was 10μ in the former case and 30μ in the latter case.2. The maintenance time of buffing was longer when the grain size of tripolite was finer or neutralization value of the grease was larger.