bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Interfacial Oxide Thickness on Titanium Silicide Formation
Authors: Donnelly J. , Brun N. , Pantel R. , Normandon P. 
Published: March 2011

ABSTRACTTiSi2 formation on various substrates has been widely investigated in the past and one of the critical parameters has been found to be the quality of the interface before deposition. In this paper the quality of the suicide formed on a range of oxides, from lnm to 15nm, has been systematically studied using sheet resistance measurements, Scanning Electron Microscopy, Atomic Force Microscopy and Auger Electron Microscopy. The critical thickness, above which the quality of the suicide formed is affected, was found to be 2.2nm and no suicide was detected > 13.0nm. A notable difference in the suicide formation occured in a narrow band around 5.0nm. It is proposed that this is the transition region in which the oxide becomes the main source of Si for TiSi2 formation rather than the substrate.
Plasma Etching Characteristics of Sputtered Tungsten Films
Authors: Franssila S. , Molarius J. M. , Saarilahti J. 
Published: March 2011

ABSTRACTThe relationship between microstructure of tungsten thin films and plasma etching properties has been studied. Rutherford backscattering, nuclear reaction analysis 16O(α,α)16O, X-ray diffraction, and resistivity measurements have been used to characterize the sputter deposited films. Independent of deposition pressure, the films were all high density, low oxygen (<1 at%), low resistivity and bccot-phase. Etch rate differences of 40% were measured in pure SF6, whereas only 10% differences were seen in SF6/Cl2 and SF6/O2BCi3 plasmas. Intentional oxygen doping (up to 2 at-%) increases the etch rate in pure SF6 plasma by 75%, wherasthe etch rate in SF6/O2/BCl3 plasma only increases 25%. The role of film density (porosity) and oxygen incorporation on etching mechanism are discussed.
Role of Teos in Improved Quality Pteos and O3-TEOS CVD SiO2 Films
Authors: Bourgeois Mark A. , Ramkumar K. , Saxena Arjun N. 
Published: March 2011

ABSTRACTThe effects of TEOS (Tetra-ethyl-ortho-silicate) concentration on the physical, chemical and electrical characteristics of undoped SiO2 films deposited by plasma (PECVD) and thermal CVD (ThCVD) processes, are described. It is shown that the (TEOS/O3) or (TEOS/O) ratio strongly influences the various film properties. The uniformity of film thickness is better at higher (TEOS/O3) or (TEOS/O2) ratios in both processes. In ThCVD the SiO2 films are denser (low etch rate) when deposited at low (TEOS/O3 ) ratio. This study has shown that the TEOS concentration can be used to tailor film properties.
Interface Reaction and Atomic Transport During COSi2 Film Formation
Authors: Xiao Z. G. , Honeycutt J. W. , Rozgonyi G. A. 
Published: March 2011

ABSTRACTThe formation process of COSi2 films grown from Co deposited on a Si single crystal was investigated as a function of very short annealing times by transmission electron microscopy and x-ray diffraction. Information on the interfacial reactions and atomic transport phenomena was obtained from a microstructural analysis of the CoxSiy layers formed. It was demonstrated that Co is the dominant diffusion species during COSi2 formation. Co atoms are generated at the COSi2/COSi2 interface via the reaction 2CoSi=CoSi2+Co and diffuse to the COSi2/Si interface, where they react with Si by Co+2Si=CoSi2. Direct microscopic evidence indicates that diffusivity of Co atoms along a COSi2 grain boundary greatly exceeds that through the COSi2 lattice. The grain boundary diffusion coefficient is estimated to be up to 100 times larger than the lattice diffusion coefficient. On this basis the influence of grain size on COSi2 film formation is discussed.
Interaction of A12O3-CAPPED Au/Zn/Au and Au/Te/Au Contacts With (001)GaAs Substrates
Authors: Lin X. W. , Liliental-Weber Z. , Washburn J. , Piotrowska A. , Kaminska E. 
Published: March 2011

ABSTRACTHREM,TEM, and EDX were employed to study the cross sections of Au/Zn/Au and Au/Te/Au contacts to [001]-oriented GaAs substrates. The metal contacts fabricated by sequential vapor deposition were capped with an A12O3 thin film to form a closed system when subjected to a 420°C anneal for 3 min. For an as-deposited Au/Zn/Au/GaAs specimen, Zn was found to react with Au to form ordered phases of Au3Zn. These phases were found to be stable upon annealing. The interface between the annealed metallization and GaAs exhibited the same degree of uniformity and planarity as that of the as-deposited specimen. For a Au/Te/Au/GaAs specimen, annealing resulted in epitaxial growth of Ga2Te3 grains, forming a basically flat interface with GaAs, while Au single-crystal grains were found to protrude rather extensively into GaAs to form a facetted interface with the substrate.
Refractory Ohmic Contacts Formed by Electroless Deposition of Palladium and Nickel Onto N-InP
Authors: Stremsdoerfer G. , Wang Y. , Martin J. R. , Souteyrand E. 
Published: March 2011

ABSTRACTNi and Pd layers have been elaborated from chemical process on (100) oriented and 1018 doped n-InP substrates. The electrical and structural characteristics of these contacts have been investigated. Good refractory ohmic contacts were obtained by the annealing of these heterostructures. The ohmic quality of chemical contacts as well as those obtained with evaporated contacts is attributed to both the presence of crystallized compounds (NiP; Ni2P; PdIn3 and Pdln) and to superficial degenerescence of InP due to a phosphorus excess laying in the interphase.
Silicon Precipitate Detection in Al-Si and Al-Si-Cu Metal Interconnect by Thermal Wave Imaging
Authors: Ritz K. N. , Welles C. G. , Smith W. L. , Bivas A. 
Published: March 2011

ABSTRACTControlling the size and distribution of silicon precipitates in aluminum alloy depositions is important for yield enhancement and reliability of small geometry metal interconnects. A non-contact and non-destructive thermal wave imaging technique is used to detect and evaluate size and density of silicon precipitates in AISi and AlSiCu alloys. The thermal wave results are corroborated with SEM and Auger data.
CVD of Copper from (β-Diketonate)CuLn Copper(I) Precursors
Authors: Chi Kai-Ming , Jain A. , Hampden-Smith M. J. , Kodas T. T. 
Published: March 2011

ABSTRACTSelective chemical vapor deposition (CVD) of copper is the focus of recent research interest as a result of possible applications as vertical interconnect material in multilevel metallization. A variety of copper(I) and copper(II) compounds have been used to deposit copper. In some cases, the compounds selectively deposit copper on various different surfaces. However, the origin of this selectivity is not unambiguously established at this stage. In order to derive a better understanding of the CVD processes, a series of copper(I) compounds (β-diketonate)CuLn have been synthesized and used as CVD precursors. The new species (fod)CuL, where fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedionate and L = PMe3, 1,5-COD, 2-butyne, BTMSA and VTMS (as defined below) are described. The CVD of copper and factors affecting selective copper deposition are discussed here.
Electrical and Microstructural Characteristics of Ti Contacts on (001)Si
Authors: Liauh H. R. , Chen M. C. , Chen J. F. , Chen L. J. 
Published: March 2011

ABSTRACTAn investigation of the electrical and microstructural characteristics of the Ti contact on silicon has been carried out. The presence of As in Ti/n+-Si samples was found to retard the formation of poly crystalline silicides compared with that in Ti/p+-Si samples with BF2+ implantation. The variations of Schottky barrier height, contact resistance and junction leakage current were correlated with microstrucxtural changes. The influences of the formation of amorphous interlayer between Ti and Si on the elctrical characteristics are discussed.
Shallow Junction Formation in Silicon: Dopant Incorporation and Diffusion Through Tungsten Silicide Films Using Gas Immersion Laser Doping (Gild)
Authors: Ishida Emi , Kramer K. -Josef , Talwar Somit , Sigmon Thomas W. , Weiner Kurt H. , Lynch William T. 
Published: March 2011

ABSTRACTWe have demonstrated a new method of doping suicide films which uses a pulsed excimer laser and a wafer cell which is filled with dopant gas species, e.g. BF3, ASF5, PF5. A spatially homogenized 308nm XeCl pulsed laser is used as a heating source to drive adsorbed dopant gas species into the suicide, as well as to outdiffuse dopants into the silicon substrate. The total dose, interface concentration, and junction depth, are controlled by varying the number of laser pulses. High interface concentrations (Cint >1020 atoms/cm3) and shallow junctions (Xj < 1500Å) are obtained using this technique. Laser irradiation also results in smoothing of the suicide film.
Studies on the Nucleation Behaviors of Precipitation in Aluminum Metallization
Authors: Wang Jen-Ren , Lin Jian-Yang , Hwang Huey-Liang 
Published: March 2011

ABSTRACTIn order to simulate the precipitation effect during the aluminum metallization in the VLSI processing, an analytical model was constructed in this work. The nucleation behaviors of the silicon and copper precipitates within the aluminum - 1.0 weight percent silicon - 0.5 weight percent copper were studied. The volume free energies and interfacial energies were estimated, and the activation energy barriers for the precipitate formation were calculated. Silicon precipitate is more likely to nucleate than copper precipitate due to its lower interfacial energy and strain energy. The mechanical and electrical properties of the aluminum interconnects can be improved by the precipitate hardening.
Reliable Metallization System for Flip-Chip Optoelectronic Integrated Circuits
Authors: Wada Osamu 
Published: March 2011

ABSTRACTThermal stability of evaporated Pd, Pt and Rh films as reaction barriers to Au-Sn solder was studied for the application to fl1p-ch1p optoelectronic integration. Sn 1n the solder diffused preferentially Into a barrier metal uniformly to produce more stable IntermetalUc phases for all three metals. Pt and Rh exhibited sufficiently samll 1nterd1ffus1on coefficients with high activation energies 1n the temperature range of device operation (Pt: 1.35 eV, Rh: 1.95 eV). This result demonstartes the usefulness of Pt and Rh 1n practical flip-chip Integrated circuit fabrication. Aging test was conducted on fl1p-ch1p GalnAs/InP p-1-n photodiodes with Au-Sn/Pt metallization and no severe degradation was observed over 3400 h at 180 ° C. The same metallization techniques were applied 1n the fabrication of 10 Gbps optoelectronic Integrated receivers as well as quad p-i-n photodiodes for coherent optical receivers.
Effects of Line Width, Thickness and Alloy Temperature on the Breakdown Energy of thin Aluminum Lines
Authors: Jairath Rahul , Gadepallu Katnesh , Bradford Brad , Shibley James , Castel Egil , Lahri Rajeeva 
Published: March 2011

ABSTRACTReliability issues have assumed greater importance as critical dimensions in microelectronic devices have entered the sub-micron regime. Wafer level reliability tests have been performed to study the breakdown energy of aluminum. 1500Å, 3500Å, 5500Å aluminum films were sputter deposited at 400 °C on oxide-on-silicon substrates. Test structures with line widths varying from 1 μm to 10 μm were defined on the metal film. The aluminum lines were then passivated using a stacked layer of silicon dioxide and silicon nitride. Finally, the substrates were alloyed at temperatures from 400°C to 450 °C. An attempt has been made to minimize process variability effects by processing the substrates through the same process conditions as far as possible. Failure was induced by stressing the metal lines with high DC current densities and at a constant slew rate. The samples were characterized using optical and scanning electron microscopy. Failure analysis of the samples processed under the different conditions will be discussed.
Ion Implantation to Inhibit Corrosion of Copper
Authors: Dmg P. J. , Lanford W. A. , Hymes S. , Murarka S. P. 
Published: March 2011

ABSTRACTIon implantation of boron and aluminium is used to passivate copper surfaces. Such a process modifies the copper only near its surface without affecting copper's desirable bulk properties. The present experiments show that implant doses as low as 1015 ions/cm2 of either boron or aluminium can reduce the oxidization rate by one order of magnitude or more compared to non-implanted samples.
Etitanium Nitride Barrier Metallization Techniques for ULSI Semiconductor Devices
Authors: Chiang Sunny , Hendel Rudi , Zhang Fang 
Published: March 2011

ABSTRACTHigh quality barriers of sputter deposited titanium nitride (TiN) are critical elements of advanced ULSI integrated circuits. We have examined the effect of eight variables on eight parameters which may affect device characteristics and the ability to incorporate TiN into the production process. We will discuss the interaction of the variables with the properties of the deposited TiN and indicate in particular the combination of variables which lead to optimum barrier properties.
Co/SixGe1-x Alloy Formation on Strained SixGe1-x Layers
Authors: Ridgway M. C. , Elliman R. G. , Hauser N. , Baribeau J. -M. , Jackman T. E. 
Published: March 2011

ABSTRACTThe thermally-induced Co/SixGe1-x reaction has been studied for a series of isochronal (25–600°C/20 min) and isothermal (600°C/u-240 min) annealing sequences using Rutherford backscattering spectrometry, transmission electron microscopy and sheet resistance measurements. Annealing at 600°C yields a reacted surface layer comprised of Si-rich CoSixGe1-x, Ge-rich SiyGe1-y and possibly CoSi2, with the two former constituents exhibiting a degree of epitaxial alignment with the substrate. The formation of Co/SiSixGe1-x alloys is discussed in terms of the ternary phase diagram.
Detection of Surface Response to Chemical/Mechanical Planarization of Silica Films
Authors: Trogolo Jeffrey A. , Rajan Krishna 
Published: March 2011

ABSTRACTChemical/mechanical (C/M) planarization is a technique that has received attention lately due to the industry-wide trend toward multilevel device processing. In most multilevel schemes, the most commonly planarized layer is the interlevel dielectric, usually an oxide. In order to understand the response of this oxide layer to the planarization process, the authors have addressed the issues of chemical and structural effects of C/M planarization on silicon dioxide films. Transmission electron microscopy (TEM) and Fourier transformed infrared (FTIR) spectroscopy were used to examine the films and revealed that there are chemical and structural changes that occur within 200 nm of the film surface.
Stability of Sputter Deposited Al-Cu Bilayers on SiO2.
Authors: Nandan R. , Murarka S. P. , Pant A. , Shepard C. , Lanford W. A. 
Published: March 2011

ABSTRACTAn investigation of the stability and electrical characteristics of Aluminum-Copper bilayer films on SiO2 has been carried out. In this investigation, a thin layer of sputtered aluminum is used as a diffusion barrier/adhesion promoter between the copper and SiO2. The electrical performance of these structures when subjected to thermal cycles and applied biases is determined. The interactions and diffusion of copper through aluminum into SiO2 was investigated using both blanket films and MOS capacitors. Results are compared with those obtained from structures of Al and Cu metallization on SiO2. Samples were annealed at various temperatures in the range of 200°C to 500°C. Analysis using four-point probe resistivity measurements, X-ray diffraction, and Rutherford Back Scattering were carried out. MOS capacitors are used to establish performance under applied bias. Capacitance-Voltage characteristics of formed alloys are discussed. These results will be presented and discussed in view of the applicability of aluminum as the adhesion promoter for copper interconnections on SiO2.
Transient Response and Space Charge Effects in Extrinsic Photoconductors
Authors: Haegel N. M. , Latasa C. A. , Fong G. L. , White A. M. 
Published: March 2011

ABSTRACTTransient response times for extrinsic photoconductors under constant voltage bias have been calculated using a variable finite-difference technique. We find that the transient response to a step function increase in photon signal is determined by the build-up of a space charge barrier to counteract out-diffusion and sweep-out. Transient times on the order of 10−2 – 10−4 s are found for 20–500 μm thick detectors under the photon backgrounds typical of infrared astronomy and other low background spectroscopy applications.
Photoinduced Space Charge Effects on Current Noise in Photoconducting Insulators
Authors: Carbone A. , Mazzetti P. 
Published: March 2011

ABSTRACTA set of experimental measurements concerning both current noise and conductance relaxation curves in CdS and CdSe photoconductors has shown the existence of a relationship between the noise power spectrum and the Fourier transform of the phototransient curve. Some of these experimental results have already been published. It appears that at least two different noise components contribute to the total power spectrum. The first component, which dominates the low frequency part of tile spectrum, is strictly related to the behaviour of the relaxation curve. Indeed, it can be attributed to the fluctuation of the photoinduced positive trapped charge and consequently of the potential barrier at the interface electrode-photoconductive material. The second component, on the contrary, is practically independent of the light wavelength, and represents an intrinsic noise component related to the generation-recombination and trapping processes within the photoconductor. In this paper we present a theory accounting for both the photoinduced and the intrinsic noise component. This theory fits well to the experimental data concerning the dependence of noise on light intensity and wavelength, using the parameters obtained from the phototransient and photoconductance measurements performed on thle same specimens. It also gives tile correct order of magnitude of the measured absolute value of the noise power spectrum.
Ion-Implanted Germanium Far-Infrared Photodetectors
Authors: Wua I. C. , Hailer E. E. 
Published: March 2011

ABSTRACTGermanium Blocked Impurity-Band (BIB) detectors, which have potential applications for space-born far infrared astrophysics observations, have been fabricated by means of boron ion implantation on high-purity Ge substrates. These devices are sensitive beyond the cutoff wavelength of Ge photoconductors doped with shallow acceptors. The extended cutoff wavelength increases with applied bias and can reach up to 200μm at very low dark currents of less than 100 electrons/sec. In order to enhance the photo-response, high-energy (3MeV) implantation has been used to form a thicker infrared-active layer. The influence of both ion-implant energies and post-implant anneals on the performance of detectors will be presented. Generation of excess donors in the boron implanted region has been observed. Their origin and effect of device performance will be discussed.
Applications of Optoelectrochemical Impedance Measurements on Electrolyte/Dielectric/Semiconductor Structure:Cartographic Analysis
Authors: Martin J. R. , Royer P. , Souteyrand E. 
Published: March 2011

ABSTRACTThe use of a weak modulated illumination with above-bandgap light energy as a probe scanning a Electrolyte/Dielectric/Semiconductor structure under electrochemical potentiostatic polarization gives an opportunity to obtain qualitative cartographies of different electrical parameters characterizing the Semiconductor/Dielectric interface.
The Confining Potential for Carriers in Planar Doped GaAs and the Effect of Photoexcitation
Authors: Richards D. , Wagner J. , Ploog K. , Fischer A. 
Published: March 2011

ABSTRACTSingle Be and Si δ-doped layers in GaAs have been investigated by Raman spectroscopy. GaAs/AlxGa1-xAs heterointerfaces, placed 30nm from the dopant spike on either side, facilitate optical measurements by the confinement of photogenerated minority carriers. Self-consistent subband calculations have been performed to compute the subband structure of the two-dimensional electron or hole gas which is confined by the space-charge induced potential well at the δ-doping layer. Upon increasing photoexcitation, the increase in density of photocreated electrons in the Be structure is clearly seen in the polarised Raman scattering spectrum by the appearance, and subsequent increase in frequency, of the electron plasmon modes. The electric field at the top GaAs/AlxGa1-xAs interface is monitored by measuring the strength of electric field induced LO phonon scattering.
Exciton Transitions in Narrow GaAs/AlxGal-x As Quantum Wells
Authors: Russo O. L. , Rehn V. , Nee T. W. , Cole T. L. , Theis W. M. , Schwartz C. 
Published: March 2011

ABSTRACTElectroreflectance (ER) measurements were made on GaAs/AxGal-x As coupled quantum wells at room temperature and at 77K. The close coupling of the narrow (28.3 A) barriers resulted in splitting of the hole and electron subband levels which was observed at both temperatures. As a first approximation, the confining potential was assumed to be due to the barrier alone; electric field effects of the modulating potential and trapped interfacial charge were considered to be negligible. The dominant heavy holeconduction and light hole-conduction transitions observed at 300K were at 1523meV and 1539 meV respectively, although other weaker transitions were also resolved.
A Theoretical Study of Band Offset Modification at the InAs/GaAs Interface
Authors: Shen T-H. , Matthai C. C. 
Published: March 2011

ABSTRACTWe present the results of pseudopotential calculations on the InAs/GaAs system with and without interlayers of Ge at the interface. We find that the band alignment depends critically on the positioning of the interlayer at the interface and on the number of monolayers substituted. The results can be explained with recourse to a simple model based on charge transfer between the atoms across the interface.
Transmission Electron Microscopy Study of Epitaxial Co/Au and Co/Pd (111) Multilayers
Authors: de Veirman A.E.M. , Hakkens F. , Coene W. , Den Broeder F.J.A. 
Published: March 2011

ABSTRACTThe results of a transmission electron microscopy study of Co/Au and Co/Pd multilayers are reported. Special emphasis is put on the epitaxial growth and the relaxation of the misfit strain of these high misfit systems. In bright-field cross-sectional images, periodic contrast fringes are observed at the interfaces, which are the result of Moiré interference and which allow determination of the degree of misfit relaxation at the interface. It was established that 80-85% of the misfit is relaxed. From high resolution electron microscopy images the Burgers vector of the misfit dislocations was derived, being a/2<110> lying in the (111) interface plane. The results obtained for the Co/Au and Co/Pd multilayers will be discussed in comparison with those obtained for a bilayer of Co and Au.
Films Grown on Vicinal GaAs(111) Substrates By Molecular Beam Epitaxy
Authors: Yang K. , Schowalter L. J. 
Published: March 2011

ABSTRACTThe faceted surface morphology of films grown on on-axis GaAs(111) substrates in the reconstruction regime is studied with an atomic force microscope. It reveals that facets are vicinal surfaces. Surface morphologies of films grown on substrates tilted toward different directions have been compared. An explanation is given for all observed surface morphologies. Smooth films can only be obtained on substrates tilted toward [211] in the surface reconstruction regime.