bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heteroepitaxy of Si/Si1−xGex Grown by Remote Plasma-Enhanced Chemical Vapor Deposition
Authors: Hsu T. , Qian R. , Kinosky D. , Irby J. , Anthony B. , Banerjee S. , Tasch A. , Magee C. 
Published: June 2019

ABSTRACTLow temperature heteroepitaxial growth of Si1−xGex films with mole fractions “x” ranging from 0.07 to 0.72 on Si(100) has been achieved by Remote Plasma-enhanced Chemical Vapor Deposition (RPCVD) at substrate temperatures of 305°C and 450°C. Reflection High Energy Electron Diffraction (RHEED), Transmission Electron Microscopy (TEM), and Secondary Ion Mass Spectroscopy (SIMS) were employed to characterize the crystallinity, composition and interfacial sharpness. The Si1−xGex films with thickness below the critical layer thickness were confirmed to have excellent crystallinity with defect density below the sensitivity of TEM analysis (105 cm−2). The Ge profile, from SIMS analysis, in a Si/Si0.8Ge0.2/Si/Si0.82Ge0.18 multilayer structure was found to have a transition width of 30Å/decade, which is the resolution limit of SIMS analysis. There is no Ge segregation observed at the Si/Si1−xGex interface. A superlattice structure with 24 pairs of Si(60Å)/Si0.8Ge0.2 (60Å) layers has been successfully grown by RPCVD at 450°C. From cross-sectional TEM analysis, very low defect densities and abrupt Ge transitions were confirmed.
Ion Beam Sputter Deposition Of Ferroelectric Oxide Thin Films
Authors: Graettinger Thomas M. , Auciello O. , Ameen M. S. , Al-Shareef H. N. , Gifford K. , Kingon A. I. 
Published: June 2019

ABSTRACTFerroelectric oxide films have been studied for their potential application as integrated optical materials and nonvolatile memories. Electro-optic properties of potassium niobate (KNbO3) thin films have been measured and the results correlated to the microstructures observed. The growth parameters necessary to obtain single phase perovskite lead zirconate titanate (PZT) thin films are discussed. Hysteresis and fatigue measurements of the PZT films were performed to determine their characteristics for potential memory devices.
Preparation Of Bi4Ti3O12 Films by ECR Plasma SpuTtering
Authors: Masumoto Hiroshi , Goto Takashi , Masuda Youichirou , Baba Akira , Hirai Toshio 
Published: June 2019

ABSTRACTEpitaxially grown films of Bi4Ti3O12 (BIT) were prepared on the substrate of a sapphire single crystal heated at 650°C using a sintered Bi4Ti3O12 target by electron cyclotron resonance (ECR) plasma sputtering. The BIT film of the same composition with the target was obtained under the conditions of microwave power(Mp) higher than 500 W and RF power(Rp) between 300 to 700 W. Increasing Mp or Rp, the deposition rate of the film was increased and the surface of the film became rough. The film exhibiting flat surface, good crystalline orientation and stoichiometric composition was prepared at such the high rate as 3.5 Å/sec under the conditions of Mp=500W and Rp=500W. Dielectric constants(1KHz) of the films deposited on (1120), (1102) and (0001) of sapphire were 93, 121 and 90, respectively, and refractive indexes of each films for the wave length of 632 nm were 2.32, 2.38 and 2.37, respectively.
Molecular Dynamics Simulations of Thin Film Diamond Growth
Authors: Pailthorpe Bernard A. , Knight Peter 
Published: June 2019

ABSTRACTThe growth of synthetic diamond thin films is studied by molecular dynamics computer simulations of low energy carbon atom deposition onto a low temperature diamond (111) surface. A previously reported Stillinger Weber potential, reparameterised for sp3 bonding in carbon using Hartree-Fock calculations for small carbon clusters, is used to model the interatomic interactions. The penetration of 1-100eV neutral carbon atoms into a (111) surface of carbon at 100K and the resultant surface atom rearrangements and induced film stress are studied. For intermediate energies (20-60eV) the incident atoms penetrate beneath the exposed (111) surface and increase the lateral compressive stress in the diamond film. It is suggested that diamond films grow from below the exposed surface in a region of locally high stress and tetrahedral coordination. The predicted radial distribution functions agree reasonably with electron diffraction studies of vacuum arc deposited amorphous diamond.
Oxidation Of AIN-Al2O3 Composite Film Prepared By Microwave Plasma CVD
Authors: someno Yoshihiro , sasaki Makoto , Hirai Toshio 
Published: June 2019

ABSTRACTThermal oxidation resistance, in a temperature range of 600 to 1100° C, of AIN-Al2O3 composite, AIN and θ-A12 O3 films has been studied. The films were prepared by microwave plasma CVD using an AlBr3 -H2 -N2 -Ar gas system at a substrate temperature of 430° C. AIN-Al2O3 composite film was found to have good surface stability below an oxidaton temperature of 1100°C and to have the best properties for insulation film.Key words: microwave plasma CVD, AIN-Al2O3 composite, passivation film, oxidation resistance, AlBr3
The Influence of Ion Bombardment on the Surface Composition of 70 wt% Cu-30 wt% Zn Alpha-Brass
Authors: Franetovic Vjekoslav 
Published: June 2019

ABSTRACTThe short time ion bombardment during ion milling resulted in a dramatic change in the surface composition of alpha-brass, selectively removing up to 2/3 of the Zn atoms during the first 5 to 10 minutes of ion milling. This differential sputtering occurred at various ion beam energies and at target temperatures as low as −196°C (LN2 temperature). The effect of differential sputtering completely disappeared after ion milling times in excess of three hours. Such a dramatic change in composition could not be attributed either to a difference in sputtering yield or to different ion milling conditions. It was shown that under constant ion milling conditions this differential sputtering depends strongly and only on the condition of the foil surface. The unexpected disappearance of the effect of differential sputtering with time was attributed to stabilization of a characteristic surface topography produced by long time ion bombardment.
Magnetron-Enhanced Reactive-Ion-Etching of Al-1%Si-2%Cu Alloy
Authors: Fu C. Y. , Hsu R. , Malba V. 
Published: June 2019

ABSTRACTPlasma etching of Al-1%Si-2%Cu presents serious challenges in corrosion, residue, and critical dimension (CD) control in single wafer etchers. One approach is to pattern the metal with oxide mask so chlorine can no longer be trapped in resist and sidewall polymers to cause corrosion. The magnetron-enhanced reactive-ion-etching (MERIE) offers a high degree of ionization at very low pressure, so anisotropic etching with reasonably high etch rate can be achieved even without sidewall protection. This paper summarizes our MERIE process characterization in terms of the effects of SiCl4 flow rate and plasma power on selectivity and CD control using an oxide mask. Typical etching was performed at 1000 watts and 40 sccm SiCl4 with the unthrottled pressure at 4.0 mTorr and a self-induced dc bias of 75 V. A 2-minute NF3 plasma at 250 watts and 100 sccm of NF3 flow served as the passivation step. This metal etch process has been successfully implemented in a doublelayer-metal interconnect technology.
Universal Energy Dependence of Sputtering Yields At Low Ion Energy
Authors: Muri J. , Steinbrüchel Ch. 
Published: June 2019

ABSTRACTSputtering yields Y(E)at ion energies E keV are shown to be described by the equation Y(E) = A(En - ) where A, n, and the threshold energy Eth are constants characteristic for a particular projectile/target combination. Examination of a wide variety of systems reveals that n = 0.5 provides an excellent universal representation of a large body of data, including physical sputtering of metals by noble gas ions, selfsputtering of metals, as well as physical and chemical sputtering of Si and SiO2. The above value for n is consistent with a 1/r4 power law atom-atom interaction potential within Sigmund's theory of sputtering. Another conclusion is that the effect of Eth on Y(E) must be taken into account at ion energies as high as 1 keV, not just near the sputtering threshold.
Experimental and Theoretical Investigations on the Interrelation of Charge Exchange Processes and Energy Loss of Particles at Metal Surfaces
Authors: NÄrmann A. , Heiland W. , Monreal R. , Flores F. , Echenique P. M. 
Published: June 2019

ABSTRACTWe present experiments and a theoretical model for the energy loss distribution of specularly reflected particles after slow (2-5 keV) He ions have been impinging on a Ni(110) surface under grazing incidence. The energy spectra of the backscattered particles are asymmetric with the low-energy tail falling off more slowly than the high-energy tail does.This asymmetry is accounted for by considering charge exchange events during the interaction with the surface. The main neutralization channel for this system is the Auger-neutralization from the conduction band into the He-1s ground state. The transition rate for this process was calculated from first principles. Assuming that the ‘friction coefficient’ for the system particle-surface depends on the charge state of the particle, we calculate the energy lost by a particle during the interaction as a sum of different contributions belonging to different charge states.
ECR Plasma Etching Technology for ULSIs
Authors: Samukawa Seiji 
Published: June 2019

ABSTRACTA new electron cyclotron resonance (ECR) plasma etching technology has been developed to realize simultaneously high selectivity, high rate and anisotropic etching for phosphorus doped poly-Si and WSix/poly-Si at a low ion energy. In this technology, a substrate is located around the ECR position (875 gauss position) in an ECR plasma. As a result of ECR position etching, under the low pressure of 5 × 10−4 Torr, a high etching rate and an infinite selectivity to SiO2 etching are realized by using C12/O2 and Cl2/O2/SF6 etching gas.
Solid State NMR Studies of the Adsorbed States of Formic Acid on Y Zeolites
Authors: Duncan T. Michael , Vaughan Robert W. 
Published: June 2019

ABSTRACTSeveral multiple-pulse double-resonance NMR techniques have been applied to isolate and characterize the spectra of the adsorbed states of formic acid on two Y zeolites. The two surface states, bidentatT3 and ynidentate, possess different motional properties and 13C - H cross-polarization techniques may be used to separate the spectra. The 13C chemical shift anisotropy is founa to iorrelate with the symmetry of the formate species. The H spectrum of the carbonyl hydrogen, selectively observed with the dipolardifference method, indicates that this hydrogen becomes more acidic upon adsorption.
Influence of the Structural Parameters of Polysilicon Films on the Piezoresistive Properties at High Temperature
Authors: Kleimann P. , Semmache B. , Berre M. Le , Barbier. D. 
Published: June 2019

AbstractPolycrystalline silicon, used as a transducing material in high temperature Silicon On Insulator piezoresistive pressure sensor, is well known to be strongly dependent on the process parameters. Indeed depending on the deposition, doping and annealing conditions, the structural parameters of polysilicon namely grain size and texture may be very different. We use here a complete model of the piezoresistivity in polysilicon including a significant effect at grain boundaries to study the influence of structural parameters on the resistivities, gauge factors and their thermal drifts between room temperature and 200°C. The model validity has been verified experimentally for two types of polysilicon materials (LPCVD at 620°C and LPCVD at 580°C), subsequently B-doped (from 9×1018 to 9×1019 cm−3) and annealed by Rapid Thermal Annealing at 1100°C/20s and 1100°C/40s respectively. A good agreement between theoretical and experimentally determined resistivities and gauge factors at a variable temperature is observed for the two types of polysilicon materials considering different grain sizes with a <110> dominant texture for LPCVD 620°C series and no preferential texture for LPCVD 580°C series.
Effect of Thermoelastic Stress on the Pressure Response of a Composite SiO2/Si Membrane
Authors: Malhaire C. , Berre M. Le , Barbier D. 
Published: June 2019

AbstractThe layout design of membrane-based sensors such as Silicon On Insulator micromachined pressure sensors requires the knowledge of the mechanical behavior of the complete structure as a function of pressure and temperature. Unfortunately, as a result of thermal mismatch, large stresses usually exist in composite SiO2/Si membranes that significantly affect the pressure response of such sensors, We present here an original study on the 3D-FEM modeling (ANSYS) of pre-stressed SiO2/Si membranes submitted to pressure. The model of thermoelastic stress (without any applied pressure) has been first validated by optical profilometry deflection measurements. 2.94 mm width membranes with Si thickness varying from 10.7 to 19.3 μm, as measured by FT-IR, and covered with 1.46 μm thick thermal oxide grown at 1130°C, have been studied. Thermoelastic deflections from I to 25 μm have been measured for decreasing Si thickness in agreement with the simulation. The simulated longitudinal stress relaxation over the oxide varies from 5 to 40 MPa between the membrane center and the frame when decreasing membrane thickness. Under pressure (10 and 100 mbar) and for a 19.3 μm thick composite membrane (0.5 )μm thick oxide), the calculated strains can exceed by 20% that of a bare Si one, due to a lower overall stiffness produced by the oxide compressive stress.
Charge Trapping and Degradation Properties of PZT Thin Films for MEMS
Authors: Kim Hyeon-Seag , Polla D. L. , Campbell S. A. 
Published: June 2019

AbstractThe electrical reliability properties of PZT (54/46) thin films have been measured for the purpose of integrating this material with silicon-based microelectromechanical systems. Ferroelectric thin films of PZT were prepared by metal organic decomposition. The charge trapping and degradation properties of these thin films were studied through device characteristics such as hysteresis loop, leakage current, fatigue, dielectric constant, capacitancevoltage, and loss factor measurements. Several unique experimental results have been found. Different degradation processes were verified through fatigue (bipolar stress), low and high charge injection (unipolar stress), and high field stressing (unipolar stress).
Experimental Analysis of the Process of Anodic Bonding using an Evaporated Glass Layer
Authors: Choi W. B. , Ju B. K. , Lee Y. H. , Haskard M. R. , Jeong S. J. , Lee N. Y. , Sung M. Y. , Oh M. H. 
Published: June 2019

AbstractA silicon-to-silicon anodic bonding process using a glass layer deposited by electron beam evaporation will be described. Corning #7740 Pyrex glass was used the source material of electron evaporation. From Auger electron spectroscopy (AES), the composition of the deposited glass layer is nearly same as that of the bulk Pyrex glass plate. Wafers are bonded at a temperature as low as 135 °C with an applied voltage as small as 35Vdc, enabling of this technique to be applied to vacuum packaging of microelectronic devices. Experimental results reveal that an evaporated glass layer of more than 1 μ m thick is suitable for anodic bonding. Finally, The role of sodium ions in anodic bonding was also studied by investigating the theoretical bonding mechanism and examining the results of secondary ion mass spectroscopy (SIMS) analysis.
Titanium-Nickel Shape Memory Thin Film Actuators for Micromachined Valves
Authors: Kahn H. , Benard W. L. , Huff M. A. , Heuer A. H. 
Published: June 2019

AbstractMicroelectromechanical valves have been fabricated from silicon wafers using standard bulk micromachining techniques, which utilize thin (2 μm) films of sputter-deposited titaniumnickel as the actuators. The TiNi shape memory alloy actuators are thermally driven by resistive heating, through the passage of an electric current. TiNi diaphragms (8.4 mm wide) are fabricated and tested in a pressure-temperature controlled fixture in order to determine the mechanical properties of the shape memory film. If a silicon island is left attached to the center of the diaphragm, this can act as a “boss” whose movement against an orifice will open and close the valve. The orifice can be etched into a second silicon wafer or machined from another rigid material. Use of mechanical spacers and external bias springs result in a normally-closed or normally-open configuration. Modulations of up to 90 percent have been observed in gas flows of up to 0.6 liter/min. Water flows as high as 5 ml/min. have been modulated by 60 percent.
Selective Electroless Copper Metallisation of Epoxy Substrates
Authors: Campion L. M. , O'reilly M. , Macauley D. J. , Kelly P. V. , Crean G. M. 
Published: June 2019

AbstractThis paper discusses the development of a novel selective electroless copper metallisation route for the plating of epoxy substrates. This has the potential for the development of a more cost effective and environmentally friendly plating process than currently available technologies. The electroless process required that the electrically insulating epoxy substrate was initially activated to catalyse the reduction of the copper (I1) salt which was in solution to a copper (0) deposit. Selective activation was achieved by coating the epoxy substrates with a new proprietary palladium compound and selectively exposing specific areas to 222nm radiation from a KrCI* excimer lamp. It has been shown that only the palladium metal and not the proprietary precursor catalyse the reaction. After selective seeding the patterned epoxy substrates were copper plated in a commercial electroless copper bath. The process conditions and effect of surface preparation on the quality and resolution of the selectively deposited copper patterns are discussed.
Design and Properties of a Thin-Film, Mems-Based Magnetostrictive Magnetometer
Authors: Kistenmacher T. J. , Osiander R. , Ecelberger S. A. , Givens R. B. , Wickenden D. K. , Murphy J. C. 
Published: June 2019

AbstractThe principles of operation of a MEMS-based magnetometer designed on the magnetoelastic effect are described. The active transduction element is a commercial (001) silicon microcantilever sputter coated with an amorphous thin film of the giant magnetostrictive alloy Terfenol-D [(Dy0.7Tb0.3)Fe2]. The easy axis of magnetization of the Terfenol-D film lies in the plane of the microcantilever and along the acicular direction. In addition to the magnetostrictive transducer, basic components include: (a) mechanical resonance of the coated-microcantilever through coupling to an ac magnetic field; and, (b) detection by optical beam deflection of the microcantilever motion utilizing a laser diode source and a position-sensitive detector. The sensitivity of this magnetostrictive magnetometer is currently 1 μT, which is three orders of magnitude better than a magnetometer based on a similar-sized piezoresistive cantilever.
Self-Passivated Copper Gates For Thin Film Silicon Transistors
Authors: Sirringhaus H. , Theiss S.D. , Kahn A. , Wagner S. 
Published: June 2019

AbstractA solution to the thin film silicon transistor gate metallization problem in active matrix liquid crystal displays is demonstrated in the form of a self-passivation process for copper. Bottom-level copper (Cu) lines are passivated by a self-aligned CrOx encapsulation formed by surface segregation of chromium (Cr) from dilute Cu1-xCrx alloys (x=0.1–2.3) at 400°C. The encapsulation is an efficient barrier for Cu diffusion into the SiNx gate insulator during the plasma deposition and transistor processing, and solves the problems of oxidation and adhesion to the glass substrate. Gate line resistivities are 4.5 to 7.5μΩcm depending on the initial Cr concentration. The performance of self-passivated Cu-gate thin film transistors is comparable to that of transistors with refractory metal gates.
Influence of Boron Diffusion on Ultra-Thin Oxides
Authors: Nigam T. , Depas M. , Heyns M. , Sofielc C. J. , Mapeldoram L. 
Published: June 2019

ABSTRACTIn this paper the effect of different annealing conditions on boron diffusion is studied for 3 nm gate dielectrics. The use of amorphous material instead of polycrystalline material and the influence of nitridation (two-step N2O oxidation) was investigated. A better control on the flatband voltage (VFB) shift was observed for amorphous-Si gate as compared to polycrystalline-Si gate. A reduction in VFB was observed for N2O oxides as compared to pure oxides, but VFB was still above the ideal value for some of the thermal treatments. A significant reduction in QBD is observed for p+ gates as compared to n+ gates. The lowest post-implantation anneal gives the highest QBD for all the different combinations.
Organic Contamination of Silicon Wafer in Clean Room Air and Its Impact to Gate Oxide Integrity
Authors: Imafuku D. , Mizubayashi W. , Miyazaki S. , Hirose M. , Wakayama Y. , Kobayashi S. 
Published: June 2019

ABSTRACTOrganic adsorbates on silicon wafer surfaces exposed to superclean room air were measured to evaluate organic contamination level of silicon wafers stored in a clean bench up to 180min. Such Si wafers were thermally oxidized and the dielectric degradation behavior were systematically investigated. It is found that a carbon contamination level of half a monolayer influences the charge to quasi-breakdown although the degradation mechanism itself remains unchanged.
Replacement of C-V Monitoring with Noncontact Cos Charge Analysis
Authors: Catmull K. B. , Cosway R. G. , Letherer B. A. , Homer G. S. 
Published: June 2019

ABSTRACTMany semiconductor processing facilities rely heavily on capacitance voltage (CV) analysis for verification of oxidation furnace cleanliness. CV provides an accepted set of electrical test parameters (Vfb, Qm, Tox Dit, etc). that can be used to monitor tube contamination levels during processing. However, two significant drawbacks of the CV technology are a) the need for costly and time-consuming deposition of MOSCAF (Metal Oxide Semiconductor Capacitor) electrodes, and b) the reduction in electrically active contaminants due to the MOSCAP processing sequence. A commercially available noncontacting technology called corona-oxide-semiconductor (COS) analysis is described here which does not require post-oxidation processing, but does measure the fundamental electrical test parameters required for process control and development [2]. The noncontact COS technology is shown to be significantly more responsive to intentionally introduced electrically active contaminants than poly MOSCAP CV. The data indicate that this difference in sensitivity is due to the immediate, processing-free nature of the COS technology.
Space Charge Analysis in Thin SiO2 Films: Local Vs. Uniform Degradation Models
Authors: Kotov A. E. 
Published: June 2019

ABSTRACTThe behavior of small MOS structures (area 3 μm2), subjected to stresses caused by electron injection, demonstrates an obvious non-parallel shift in the tunneling characteristics (NPS effect), measured in the wide current range (3·10-16 -3·10-8 A) from either tunneling interface. This paper describes and compares two different approaches for the NPS effect interpretation: uniform and local degradation models (UDM and LDM). The UDM implies a modification of the oxide tunneling barrier due to area-uniform electron trapping inside the tunneling distance which could lead to the NPS effect [14]. It is shown that any spatial distribution of negative oxide charge is inapplicable to interpret the NPS effect within the framework of the UDM. The second approach uses the assumption of small (area ∼ 10-3 μm2) structure-stable regions (SSR) formed in noncrystalline SiO2 films during thermal growth. Due to the high resistance of SSRs to the degradation - negative charge generation - electron injection is gradually localized in the SSRs, avoiding a screening effect of electron trapping. It is shown that the influence of non-uniformity in the electron injection appears to be more significant, when degraded MOS structure is tested at low voltages (NPS effect).