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1.06 μm 150 psec laser damage study of diamond turned, diamond turned/ polished and polished metal mirrors

Description: Using a well characterized 1.06 μm 150 ps glass laser pulse the damage characteristics for diamond turned, diamond turned/ polished, and polished copper and silver mirrors less than 5 cm diameter were studied. Although most samples were tested with a normal angle of incidence, some were tested at 45$sup 0$ with different linear polarization showing an increase in damage threshold for S polarization. Different damage mechanisms observed will be discussed. Laser damage is related to residual surface influences of the fabrication process. First attempts to polish diamond turned surfaces resulted in a significant decrease in laser damage threshold. The importance of including the heat of fusion in the one dimensional heat analysis of the theoretical damage threshold and how close the samples came to the theoretical damage threshold is discussed. (auth)
Date: July 24, 1975
Creator: Saito, T. T.; Milam, D.; Baker, P. & Murphy, G.
Partner: UNT Libraries Government Documents Department

8. Innovative Technologies: Two-Phase Heat Transfer in Water-Based Nanofluids for Nuclear Applications Final Report

Description: Abstract Nanofluids are colloidal dispersions of nanoparticles in water. Many studies have reported very significant enhancement (up to 200%) of the Critical Heat Flux (CHF) in pool boiling of nanofluids (You et al. 2003, Vassallo et al. 2004, Bang and Chang 2005, Kim et al. 2006, Kim et al. 2007). These observations have generated considerable interest in nanofluids as potential coolants for more compact and efficient thermal management systems. Potential Light Water Reactor applications include the primary coolant, safety systems and severe accident management strategies, as reported in other papers (Buongiorno et al. 2008 and 2009). However, the situation of interest in reactor applications is often flow boiling, for which no nanofluid data have been reported so far. In this project we investigated the potential of nanofluids to enhance CHF in flow boiling. Subcooled flow boiling heat transfer and CHF experiments were performed with low concentrations of alumina, zinc oxide, and diamond nanoparticles in water (≤ 0.1 % by volume) at atmospheric pressure. It was found that for comparable test conditions the values of the nanofluid and water heat transfer coefficient (HTC) are similar (within 20%). The HTC increased with mass flux and heat flux for water and nanofluids alike, as expected in flow boiling. The CHF tests were conducted at 0.1 MPa and at three different mass fluxes (1500, 2000, 2500 kg/m2s) under subcooled conditions. The maximum CHF enhancement was 53%, 53% and 38% for alumina, zinc oxide and diamond, respectively, always obtained at the highest mass flux. A post-mortem analysis of the boiling surface reveals that its morphology is altered by deposition of the particles during nanofluids boiling. A confocal-microscopy-based examination of the test section revealed that nanoparticles deposition not only changes the number of micro-cavities on the surface, but also the surface wettability. A simple model was ...
Date: July 31, 2009
Creator: Buongiorno, Jacopo & Hu, Lin-wen
Partner: UNT Libraries Government Documents Department

THE 110 GHz MICROWAVE HEATING SYSTEM ON THE DIII-D TOKAMAK

Description: OAK-B135 Six 110 GHz gyrotrons in the 1 MW class are operational on DIII-D. Source power is > 4.0 MW for pulse lengths {le} 2.1 s and {approx} 2.8 MW for 5.0 s. The rf beams can be steered poloidally across the tokamak upper half plane at off-perpendicular injection angles in the toroidal direction up to {+-} 20{sup o}. measured transmission line loss is about -1 dB for the longest line, which is 92 m long with 11 miter bends. Coupling efficiency into the waveguide is {approx} 93% for the Gaussian rf beams. The transmission lines are evacuated and windowless except for the gyrotron output window and include flexible control of the elliptical polarization of the injected rf beam with remote controlled grooved mirrors in two of the miter bends on each line. The injected power can be modulated according to a predetermined program or controlled by the DIII-D plasma control system using real time feedback based on diagnostic signals obtained during the plasma pulse. Three gyrotrons have operated at 1.0 MW output power for 5.0 s. Peak central temperatures of the artificially grown diamond gyrotron output windows are < 180 C at equilibrium.
Date: July 2003
Creator: Lohr, J.; Callis, R. W.; Doane, J. L.; Ellis, R. A.; Gorelov, Ya; Kajiwara, K. et al.
Partner: UNT Libraries Government Documents Department

3D Simulations of Secondary Electron Generation and Transport in a Diamond Electron Beam Amplifier

Description: The Relativistic Heavy Ion Collider (RHIC) contributes fundamental advances to nuclear physics by colliding a wide range of ions. A novel electron cooling section, which is a key component of the proposed luminosity upgrade for RHIC, requires the acceleration of high-charge electron bunches with low emittance and energy spread. A promising candidate for the electron source is the recently developed concept of a high quantum efficiency photoinjector with a diamond amplifier. To assist in the development of such an electron source, we have implemented algorithms within the VORPAL particle-in-cell framework for modeling secondary electron and hole generation, and for charge transport in diamond. The algorithms include elastic, phonon, and impurity scattering processes over a wide range of charge carrier energies. Results from simulations using the implemented capabilities will be presented and discussed.
Date: May 4, 2009
Creator: Busby,R.; Rao,T. & Dimitrov, D.A., Cary, J.R., Ben-Zvi, I., Chang, X., Keister, J., Muller, E., Smedley, J., Wu, Q.
Partner: UNT Libraries Government Documents Department

Abrasive wear behavior of heat-treated ABC-silicon carbide

Description: Hot-pressed silicon carbide, containing aluminum, boron, and carbon additives (ABC-SiC), was subjected to three-body and two-body wear testing using diamond abrasives over a range of sizes. In general, the wear resistance of ABC-SiC, with suitable heat treatment, was superior to that of commercial SiC.
Date: June 17, 2002
Creator: Zhang, Xiao Feng; Lee, Gun Y.; Chen, Da; Ritchie, Robert O. & De Jonghe, Lutgard C.
Partner: UNT Libraries Government Documents Department

Achromatically filtered diamond photoconductive detectors for high power soft x-ray flux measurements

Description: A 1 mm square diamond photoconductive detector (PCD) has been installed on the LLNL Nova laser system, for use as a broad band soft x-ray power diagnostic. The PCD is installed behind an array of pinholes, which cast multiple, overlapping images of the source onto the diamond. This allows reduction of the x-ray intensity, to avoid saturation problems, while avoiding the spectral dependency of thin film filters. The diode current is read out on a 5 GHz bandwidth scope. The system is calibrated by comparison to an absolutely calibrated array of filtered vacuum x-ray photodiodes (XRD` s) (``dante``). The time response of the PCD and its bias electronics have been characterized using the 5th harmonic (210 nm) of a short pulse (< 1 ps) Ti:sapphire laser. The data show a fast rise, limited by the 5 GHz scope bandwidth, and a slower fall off, characterized by an RC time of order 200 ps.
Date: June 2, 1998
Creator: Turner, R. E.
Partner: UNT Libraries Government Documents Department

Adaptive optics for high power beam lines using diamond crystal monochromators

Description: Preserving the high source brightness of the third generation of synchrotron radiation facilities will require that thermal and pressure deformations of the monochromator crystals be maintained within a few arc- seconds. Recent experiments at the National Synchrotron Light Source (NSLS) have demonstrated the potential of adaptive crystal optics to cope with high power densities. In this technique the crystals deformations are minimized both by an efficient water-jet cooling and by externally applied pressure loads. Thermal deformation can be reduced further with diamond crystals because of their high thermal conductivity and low coefficient of thermal expansion. In this paper we describe the results achieved by optimization of adaptive crystal optics for diamond crystals.
Date: January 1, 1992
Creator: Sharma, S.; Berman, L.E.; Hastings, J.B. (Brookhaven National Lab., Upton, NY (United States)) & Hart, M. (Manchester Univ. (United Kingdom))
Partner: UNT Libraries Government Documents Department

Adaptive optics for high power beam lines using diamond crystal monochromators

Description: Preserving the high source brightness of the third generation of synchrotron radiation facilities will require that thermal and pressure deformations of the monochromator crystals be maintained within a few arc- seconds. Recent experiments at the National Synchrotron Light Source (NSLS) have demonstrated the potential of adaptive crystal optics to cope with high power densities. In this technique the crystals deformations are minimized both by an efficient water-jet cooling and by externally applied pressure loads. Thermal deformation can be reduced further with diamond crystals because of their high thermal conductivity and low coefficient of thermal expansion. In this paper we describe the results achieved by optimization of adaptive crystal optics for diamond crystals.
Date: December 31, 1992
Creator: Sharma, S.; Berman, L. E.; Hastings, J. B. & Hart, M.
Partner: UNT Libraries Government Documents Department

Alpha-null defocus: An optimum defocus condition with relevance for focal-series reconstruction

Description: Two optimum defocus conditions are used in high-resolution transmission electron microscopy. Scherzer defocus produces an image of the specimen ''projected potential'' to the resolution of the microscope, and Lichte defocus minimizes dispersion. A third optimum defocus is best for focal-series reconstruction; alpha-null defocus maximizes transfer of high-frequency diffracted beam amplitudes into the microscope image. Beam transfer is confined by incident-beam convergence to a Gaussian ''packet'' of defocus values centered on the alpha-null defocus. For a diffracted beam hkl, with a spatial frequency of u, the envelope for incident beam convergence has null damping effect when defocus is set to -Cs. (wavelength.u)**2. On either side of this alpha-null defocus value, the damping effect of incident-beam convergence reduces diffracted-beam transfer. The position of alpha-null defocus for any spatial frequency depends only on the value of Cs, but defocus-packet width around the alpha-null defocus depends only on the convergence semi-angle. Under NCEM OAM (one-Angstrom microscope) conditions, a [110] diamond image with the correct 0.89A spacing appears when the Si (004) alpha-null defocus is selected. The alpha-null defocus should be included as the (furthest underfocus) limit for all high-resolution focal series reconstruction.
Date: February 14, 2001
Creator: O'Keefe, Michael A.
Partner: UNT Libraries Government Documents Department

Amorphous Diamond Flat Panel Displays - Final Report of ER-LTR CRADA project with SI Diamond Technology

Description: The objective of this project was to determine why diamond-based films are unusually efficient electron emitters (field emission cathodes) at room temperature. Efficient cathodes based on diamond are being developed by SI Diamond Technology (SIDT) as components for bright, sunlight-readable, flat panel displays. When the project started, it was known that only a small fraction (&lt;1%) of the cathode area is active in electron emission and that the emission sites themselves are sub-micron in size. The critical challenge of this project was to develop new microcharacterization methods capable of examining known emission sites. The research team used a combination of cathode emission imaging (developed at SIDT), micro-Raman spectroscopy (LBNL), and electron microscopy and spectroscopy (National Center for Electron Microscopy, LBNL) to examine the properties of known emission sites. The most significant accomplishment of the project was the development at LBNL of a very high resolution scanning probe that, for the first time, measured simultaneously the topography and electrical characteristics of single emission sites. The increased understanding of the emission mechanism helped SIDT to develop a new cathode material,''nano-diamond,'' which they have incorporated into their Field Emission Picture Element (FEPix) product. SIDT is developing large-format flat panel displays based on these picture elements that will be brighter and more efficient than existing outdoor displays such as Jumbotrons. The energy saving that will be realized if field emission displays are introduced commercially is in line with the energy conservation mission of DOE. The unique characterization tools developed in this project (particularly the new scanning microscopy method) are being used in ongoing BES-funded basic research.
Date: May 8, 1998
Creator: Ager III, Joel W.
Partner: UNT Libraries Government Documents Department

Amorphous Diamond MEMS and Sensors

Description: This report describes a new microsystems technology for the creation of microsensors and microelectromechanical systems (MEMS) using stress-free amorphous diamond (aD) films. Stress-free aD is a new material that has mechanical properties close to that of crystalline diamond, and the material is particularly promising for the development of high sensitivity microsensors and rugged and reliable MEMS. Some of the unique properties of aD include the ability to easily tailor film stress from compressive to slightly tensile, hardness and stiffness 80-90% that of crystalline diamond, very high wear resistance, a hydrophobic surface, extreme chemical inertness, chemical compatibility with silicon, controllable electrical conductivity from insulating to conducting, and biocompatibility. A variety of MEMS structures were fabricated from this material and evaluated. These structures included electrostatically-actuated comb drives, micro-tensile test structures, singly- and doubly-clamped beams, and friction and wear test structures. It was found that surface micromachined MEMS could be fabricated in this material easily and that the hydrophobic surface of the film enabled the release of structures without the need for special drying procedures or the use of applied hydrophobic coatings. Measurements using these structures revealed that aD has a Young's modulus of {approx}650 GPa, a tensile fracture strength of 8 GPa, and a fracture toughness of 8 MPa{center_dot}m {sup 1/2}. These results suggest that this material may be suitable in applications where stiction or wear is an issue. Flexural plate wave (FPW) microsensors were also fabricated from aD. These devices use membranes of aD as thin as {approx}100 nm. The performance of the aD FPW sensors was evaluated for the detection of volatile organic compounds using ethyl cellulose as the sensor coating. For comparable membrane thicknesses, the aD sensors showed better performance than silicon nitride based sensors. Greater than one order of magnitude increase in chemical sensitivity is expected through the ...
Date: June 1, 2002
Creator: SULLIVAN, JOHN P.; FRIEDMANN, THOMAS A.; ASHBY, CAROL I.; DE BOER, MAARTEN P.; SCHUBERT, W. KENT; SHUL, RANDY J. et al.
Partner: UNT Libraries Government Documents Department

Analysis and evaluation of processes and equipment in Tasks II and IV of the Low-Cost Solar Array Project. Quarterly report, April-July 1978

Description: The significant economic data for the current production multiblade wafering and inner diameter slicing processes were tabulated and compared to data on the experimental and projected Varian multiblade slurry, STC ID diamond coated blade, Yasunaga multiwire slurry and Crystal Systems fixed abrasive multiwire slicing methods. Cost calculations were performed for current production processes and for 1982 and 1986 projected wafering techniques.
Date: November 1, 1978
Creator: Goldman, H. & Wolf, M.
Partner: UNT Libraries Government Documents Department

Analysis of failed Stratapax-steel stud cutter elements

Description: Stratapax-steel stud bond strengths were evaluated in a quality control test fixture at loads up to 410 MPa. No failures occurred for cutter elements bonded in the first six diffusion bond runs. In the next two bond runs, Stratapax-steel stud cutter elements failed at test loads significantly less than 410 MPa. A failure analysis was performed on several of the failed cutter elements to isolate the material weakness responsible for the low load failures. Three groups of failures were identified: a cobalt depletion region on and immediately beneath the cemented carbide surface of the as-received Stratapax blanks, surface contamination at the carbide-steel bond joint and a weakness within the seel stud near the bond joint. Two additional defects were observed which were of some concern, namely, lamination line defects within the carbide portion of Stratapax blanks and severe grind damage on carbide surfaces of as-received Stratapax blanks. It was recommended that a grind schedule be included as part of the specimen preparation prior to bonding to alleviate the observed failures.
Date: April 1, 1981
Creator: Pope, L.E.
Partner: UNT Libraries Government Documents Department

Analysis of Multipactor Discharge

Description: Several comprehensive studies of radio frequency (rf) breakdown and rf heating are reported. They are of general interest to magnetic confinement fusion, rf linac, and high power microwave source development. The major results include: (1) a ground-breaking theory of multipactor discharge on dielectric, including a successful proof-of-principle experiment that verified the newly developed scaling laws, (2) an in depth investigation of the failure mechanisms of diamond windows and ceramic windows, and of the roles of graphitization, thin films of coating and contaminants, and (3) a most comprehensive theory, to date, on the heating of particulates by an electromagnetic pulse, and on the roles of rf magnetic field heating and of rf electric field heating, including the construction of new scaling laws that govern them. The above form a valuable knowledge base for the general problem of heating phenomenology.
Date: August 31, 2005
Creator: Lau, Y. Y.
Partner: UNT Libraries Government Documents Department

Analysis of the surface structure of HFCVD diamond films

Description: Structure analysis was carried out on various surface features of diamond films using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films were grown via hot filament assisted chemical vapor deposition (HFCVD) in methane and hydrogen gas mixtures. The authors investigated the surfaces of films grown under parameters selected to produce certain textures or surface features such as penetration twins or hopper shaped faces. The SEM images of these films show that the {l_brace}100{r_brace} planes are usually flatter than the {l_brace}111{r_brace}. The {l_brace}111{r_brace} planes show interesting growth features. The ``hopper`` shaped structures were imaged in the tapping mode of the AFM, and the angles between planes and their orientations have been determined. These AFM and SEM images are presented with quantitative analyses of the exposed surfaces. Detailed quantitative information will be useful in understanding the growth of these films.
Date: July 1, 1995
Creator: Mehta, P.; Feigerle, C.S.; Clausing, R.E.; Heatherly, L. & Thundat, T.
Partner: UNT Libraries Government Documents Department

Analytical and experimental studies for thermal plasma processing of materials

Description: Work continued on thermal plasma processing of materials. This quarter, ceramic powders of carbides, aluminium nitride, oxides, solids solutions, magnetic and non magnetic spinels, superconductors, and composites have been successfully synthesized in a Triple DC Torch Plasma Jet Reactor (TTPR) and in a single DC Plasma Jet Reactor. All the ceramic powders with the exception of AIN were synthesized using a novel injection method developed to overcome the problems associated with solid injection, in particular for the single DC plasma jet reactor, and to realize the benefits of gas phase reactions. Also, initial experiments have been performed for the deposition of diamond coatings on Si wafers using the TTPR with methane as the carbon source. Well faceted diamond crystallites were deposited on the surface of the wafers, forming a continuous one particle thick coating. For measuring temperature and velocity fields in plasma systems, enthalpy probes have been developed and tested. The validity has been checked by performing energy and mass flux balances in an argon plasma jet operated in argon atmosphere. Total Gibbs free energy minimization calculations using a quasi-equilibrium modification have been applied to simulate several chemical reactions. Plasma reactor modelling has been performed for the counter-flow liquid injection plasma synthesis experiment. Plasma diagnostics has been initiated to determine the pressure gradient in the coalesced part of the plasma jet. The pressure gradient drives the diffusion of chemical species which ultimately controls the chemical reactions. 4 figs.
Date: January 1, 1990
Partner: UNT Libraries Government Documents Department

Anisotropic Shock Propagation in Single Crystals

Description: Most single-crystal shock experiments have been performed in high-symmetry directions while the nature of shock propagation in low-symmetry directions remains relatively unstudied. It is well known that small-amplitude, linear acoustic waves propagating in low-symmetry directions can focus and/or form caustics (Wolfe, 1995). In this report we provide evidence for similar focusing behavior in nonlinear (shock) waves propagating in single crystals of silicon and diamond. Using intense lasers, we have driven non-planar (divergent geometry) shock waves through single-crystals of silicon or diamond and into an isotropic backing plate. On recovery of the backing plates we observe a depression showing evidence of anisotropic plastic strain with well-defined crystallographic registration. We observe 4-, 2-, and 3-fold symmetric impressions for [100], [110], and [111] oriented crystals respectively.
Date: May 26, 2005
Creator: Eggert, J; Hicks, D; Celliers, P; Bradley, D; Cox, J; Unites, W et al.
Partner: UNT Libraries Government Documents Department

Annual Scientific Progress Report: National Nuclear Security Administration Stewardship Stockpile: Academic Alliance Research Grant #DE-FG52-06NA26205

Description: The focus of this grant, entitled ''Experimental investigations of magnetic, superconducting, and other phase transitions in novel f-electron materials at ultra-high pressures using designer diamond anvils'', is to explore the novel properties of f-electron compounds under pressure, with a particular emphasis on the physics of superconductivity, magnetism, and their interactions. This report is a synopsis of the research that was undertaken from 6/2006-6/2007.
Date: July 26, 2007
Creator: Maple, M. Brian & Jeffries, Jason R.
Partner: UNT Libraries Government Documents Department

Annual Scientific Progress Report: National Nuclear Security Administration Stockpile Stewardship: Academic Alliance Research Grant #DE-FG52-06NA26205

Description: The focus of this grant, entitled 'Experimental investigations of magnetic, superconducting, and other phase transitions in novel f-electron materials at ultra-high pressures using designer diamond anvils', is to explore the novel properties of f-electron compounds under pressure, with a particular emphasis on the physics of superconductivity, magnetism, and their interactions. This report is a synopsis of the research that was undertaken from 6/2007-6/2008.
Date: July 24, 2008
Creator: Maple, M. Brian & Zocco, Diego A.
Partner: UNT Libraries Government Documents Department

ANNUAL SUMMARY RESEARCH REPORT IN PHYSICS, JULY 1, 1959-JUNE 30, 1960

Description: Research in theoretical and experimental physics is summarized. The method of Wyse and Mayall for estimation of density distributions in stellar galaxies from observed rotational velocities was extended to a more realistic model. Methods of calculating pair production or bremsstrahiung cross sections are discussed. The presence of 10 previously unreported gamma rays was observed in the decay of Ag/sup 1//sup 1//sup 3/. The photoproton yield from Be/ sup 9/ was investigated. Theoretical studies were made of a proposed new type of electron muitlplying discharge. The Scebeck coefficients of several single crystals of Mg/sub 2/Si were measured from 7 to 1000 deg K. New data were obtained on the resistivities and Hall coefficients of Mg/sub 2/Si. A new technique for measuring the thermal diffusivities of soilds was devised. A dynamic pulse-heating method was developed for measuring the specific heats of metal wires from room temperature to 1000 deg C. The specific heat of copper was determined. Methods for measuring microwave Hall mobillties in semiconductors were improved. The resistivity of sodium tungsten bronze as a function of sodium composition was obtained down to 4 deg K. Studies are being made of the frequency dependence of the resistance and capacitance of samples of AgBi. A single crystal of holmium metal was obtained by anneallng an arc-melted button and examining in fields up to 18 kllogauss. Magnetic moments in erbium crystals were investigated. The resistivities of nearly all of the rareearth metals in polycrystalline form were determined down to 1.3 deg K. Highly degassed samples of high-purity tantaium were produced. The superconductlng properties of a soild phase of mercury were investigated. The effect of pressure on the superconducting critical field curve of tin was also measured. The effect of pressure on the Curle temperature of dysprosium was measured. A study was made of the ...
Date: September 1, 1960
Partner: UNT Libraries Government Documents Department

The application of photoconductive detectors to the measurement of x-ray production in laser produced plasmas

Description: Photoconductive detectors (PCDs) offer an attractive alternative for the measurement of pulsed x-rays from laser produced plasmas. These devices are fast (FWHM approx.100 ps), sensitive and simple to use. We have used InP, GaAs, and Type IIa diamond as PCDs to measure x-rays emission from 100 eV to 100 keV. Specifically, we have used these detectors to measure total radiation yields, corona temperatures, and hot electron generated x-rays from laser produced plasmas. 5 refs., 4 figs.
Date: August 1, 1987
Creator: Kania, D.R.; Bell, P. & Trebes, J.
Partner: UNT Libraries Government Documents Department

APPLICATIONS OF BIOTECHNOLOGY IN DEVELOPMENT OF BIOMATERIALS: NANOTECHNOLOGY AND BIOFILMS

Description: Biotechnology is the application of biological techniques to develop new tools and products for medicine and industry. Due to various properties including chemical stability, biocompatibility, and specific activity, e.g. antimicrobial properties, many new and novel materials are being investigated for use in biosensing, drug delivery, hemodialysis, and other medical applications. Many of these materials are less than 100 nanometers in size. Nanotechnology is the engineering discipline encompassing designing, producing, testing, and using structures and devices less than 100 nanometers. One of the challenges associated with biomaterials is microbial contamination that can lead to infections. In recent work we have examined the functionalization of nanoporous biomaterials and antimicrobial activities of nanocrystalline diamond materials. In vitro testing has revealed little antimicrobial activity against Pseudomonas fluorescens bacteria and associated biofilm formation that enhances recalcitrance to antimicrobial agents including disinfectants and antibiotics. Laser scanning confocal microscopy studies further demonstrated properties and characteristics of the material with regard to biofilm formation.
Date: November 29, 2010
Creator: Brigmon, R.; Berry, T. & Narayan, R.
Partner: UNT Libraries Government Documents Department

Assessment of present state-of-the-art sawing technology of large diameter ingots for solar sheet material. Final report, September 1, 1977-February 28, 1978

Description: The objective of this program is to assess the present state-of-the-art sawing technology of large diameter silicon ingots (3&#x27;&#x27; and 4&#x27;&#x27; diameter) for solar sheet materials. During this program, work has progressed in: (1) slicing of the ingots with the multiblade slurry (MBS) saw, the multiwire slurry (MWS) saw and the I.D. saw, (2) characterization of the sliced wafers, and (3) analysis of add-on slicing cost based on SAMICS. Multiblade slurry slicing resulted in mechanical wafer yields of 95% for the 3&#x27;&#x27; diameter ingot and 84% for the 4&#x27;&#x27; diameter ingot (using a 230 blade package to cut 6&#x27;&#x27; ingot in length). A slicing test with the I.D. saw was performed to obtain mechanical yield versus both wafer thickness and cut rate, and the result showed a good yield (above 95%) down to 7 to 8 mils of wafer thickness for the 3&#x27;&#x27; wafers and 11 to 12 mils for the 4&#x27;&#x27; wafers if the cut rates were reduced to 1&#x27;&#x27; per minute. An ingot of 3&#x27;&#x27; in diameter and 3&#x27;&#x27; in length was sliced with a multiwire slurry saw to obtain wafer yield of about 97%; 163 wires were used, and wafer thickness and kerf width were 10 to 11 mils and 8 mils, respectively. Thickness, taper, bow, and roughness (RMS) were measured to characterize the sliced wafers. Four in. wafers sliced wih the multiblade slurry saw showed larger thickness variation (wafer to wafer) and more taper than 3&#x27;&#x27; wafers. Wafers sliced with the I.D. saw indicated that taper, bow, and roughness increased as the cut rate increased. Comparison showed the wafers cut with the I.D. saw (sliced below 3&#x27;&#x27; per minute of cut rate) and the multiwire slurry saw have much smaller values and variations than those cut with the multiblade slurry saw, indicating the need for less ...
Date: January 1, 1978
Creator: Yoo, H.I.
Partner: UNT Libraries Government Documents Department