bluuebunny/crossref_metadata_2025_split huggingface dataset:
Color Document Imaging with Amorphous Silicon Sensor Arrays
Authors: Street R. A. , Wu X. D. , Weisfield R. , Nelson S. , Nylen P. 
Published: April 2011

ABSTRACTWe describe the performance of an amorphous silicon imaging system designed for high speed (>10 frames/sec) scanning of a document. The system comprises a new page-sized sensor array with 1536×1920 pixels, an illumination source, and the readout electronics. With appropriate color filters, one can achieve color imaging of a document without the registration problems associated with linear scanners. We describe the color imaging properties and discuss how the color response, sensitivity and uniformity depend on the properties of the amorphous silicon sensors.
a-Si:H/a-SiC:H Heterostructure for Bias-Controlled Photodetectors
Authors: De Cesare G. , Irrera F. , Lemmi F. , Palma F. , Tucci M. 
Published: April 2011

ABSTRACTWe present a novel family of photodetectors based on hydrogenated amorphous Si/SiC p-i-n-i-p heterostructures. Front p-i-n and rear n-i-p diodes work one as a detector and the other as a load impedance, depending on the polarity of the applied voltage. Due to different absorption at different wavelengths, the devices operate as bias-controlled light detectors in either the blue or the red regions. The energy gap and the thickness of the two intrinsic layers have been optimized to obtain a sharp wavelength selection (centered at 430 and 630 nm) with high rejection-ratios and good quantum efficiencies. The I-V characteristics and the device time response are investigated and simulated by SPICE.
Amorphous Silicon Films from Dichlorosilane and Hydrogen
Authors: Bullock J.N. , Wagner S. 
Published: April 2011

ABSTRACTWe deposited a-Si:H thin-films by PECVD of dichlorosilane (SiH2Cl2) diluted with H2 in a DC-triode glow-discharge reactor. The dilution ratio, given as the ratio of H2 to SiH2Cl2 flows, was varied from 0 to 130 and the pressure was varied from 0.3 to 0.75 Torr as the hydrogen fraction was increased. We report on the properties of the deposition plasma and the resulting films; namely the plasma pressure-voltage characteristics and the films' chemical composition, structure, and optoelectronic properties. For hydrogen dilution ratios greater than 2:1, dense, rigid films are deposited, with optical bandgaps from 1.75 to 1.9 eV. With increasing hydrogen dilution a growth rate of 5 Å/s is maintained while photoconductivities increase and defect densities decrease. The best films are obtained at a dilution ratios of 16:1 to 32:1, where we have obtained a dark conductivity of 10−13 S/cm, a photoconductivity of 2×10−7 S/cm (at G=1020 cm-3 s−1) and a defect density of 1.5×1016 cm−3.
Chemical-Mechanical Polishing of Tungsten with Hologen-Based Slurries
Authors: Yang K. , Gutmann R. J. , Murarka S. P. , Stonebraker E. , Atkins H. 
Published: April 2011

ABSTRACTHalogen-based slurries have been investigated for chemical-mechanical polishing of tungsten. Among these slurries, Bromine-methanol-water slurry gives the best results. Depending on the polishing parameters and slurry concentration, polishing rate of the slurry for W varies from 100 nm/min to 300 nm/min, while the chemical etch rate of the slurry for W and SiO2is near zero. The W and SiO2films after polishing with the slurry show very smooth surfaces (featureless under a high quality optical microscope). The selectivity of larger than 15 has been achieved between W and PECVD TEOS oxide. Tungsten stud formation through CMP with this slurry has been demonstrated with no significant dishing in the metal.
Plasma Etching of Copper Films Using IR Light Irradiation
Authors: Hosoi N. , Ohshita Y. 
Published: April 2011

ABSTRACTCopper films are etched at a low temperature of 60 °C using a Cl2 plasma etching method with IR light irradiation. The etch rate is as high as 1 μm/min. The anisotropic Cu line patterns are obtained independent of the Cl2 gas flow rate and the etching pressure conditions. Moreover, there is no corrosion on the etched sample.
Impact of Microstructure of Alternative Al-Si-V-Pd Alloy Films on Interconnect Reliability, Compared to Al-Si-Cu
Authors: Dirks A.G. , Augur R.A. , Kordić S. , Wolters R.A.M. 
Published: April 2011

ABSTRACTDifficulty during plasma etching and post-etch corrosion are major drawbacks of Al-Si-Cu alloy films, when used for integrated circuit interconnect. Moreover, the relatively large solute mobility of Cu in Al may lead to void formation by precipitate coarsening. As integrated circuit dimensions decrease reliability issues, such as electromigration and mechanical stress voiding, are becoming increasingly important. At present several types of Al alloys are considered as possible alternatives for Al-Si-Cu: Al-Pd, Al-Sc, Al-Pd-Cu, Al-Si-Pd, Al-Si-V, Al-Si-Sc, Al-Si-Pd-Nb, and Al-Si-V-Pd. The latter quaternary alloy has been designed such as to combine the positive aspects of both Pd and V. In comparison with Cu in Al, a) the (low temperature) solid solubility is negligible for Pd and small for V, and b) the mobility is similar for Pd, but very small for V.With transmission-electron microscopy, passivated Al-Si-Cu alloy films have been studied after thermal stressing at 200 °C: ө-Al2Cu coarsening was observed together with void condensation. Lifetests on unpassivated Al-Si-V-Pd alloys at 180 °C and 2xl06A/cm2 have shown an extremely high resistance to electromigration. Electromigration and microstructural data on these quaternary alloys will be presented. These findings suggest how the microstructure is stabilized by the combined action of the V and Pd solute atoms, a) by nm-scale (A1,V) precipitates within the Al grains and b) by small (Al,Pd) particles at the Al grain boundaries. Furthermore, the key issues in terms of reliability related microstructural phenomena are both solute and solvent mobilities in grain interiors as well as along interfaces and grain boundaries. Arguments will be given showing that at low solute concentrations the metals (V and Pd) each by themselves are not effective enough to influence the solvent motion of aluminium along interfaces and grain boundaries significantly. The combination of the two metals, however, was found to be very effective.
Ohmic Contact Metallization for n-Type GaAs
Authors: Murakami M. , Oku T. , Otsuki A. , Uchibori C. J. 
Published: April 2011

ABSTRACTThe performance of GaAs devices is significantly influenced by the qualities of the substrates, Schottky and Ohmic contact materials. Development of Ohmic contact materials is far behind compared with that of the other materials. Low resistance, alloyed AuGeNi Ohmic contacts have been extensively used in the current manufacturing GaAs devices. However, extension of usage of these devices to Very Large Scale Integration levels requires the contacts with excellent thermal stability, shallow diffusion depth, and smooth contact surface in addition to low contact resistance. In the present paper recent studies for development of Ohmic contacts which improve the poor contact properties of the alloyed Ohmic contacts are reviewed.
Low-Resistivity Non-Alloyed Ohmic Contacts to p- and n-Gaas Using In-Situ Integrated Process
Authors: Hong M. , Vakhshoori D. , Mannaerts J. P. , Kwo J. 
Published: April 2011

ABSTRACTVery low-resistivity non-alloyed ohmic contacts (Rc) to both p- and n-GaAs were realized using molecular beam epitaxy (MBE) in a vacuum integrated system. Three different metals of Au, Ag, and Nb were in-situ deposited on (1) p+-GaAs which was heavily Be-doped either in a uniform doping or with a 5-doping scheme; and (2) n+-GaAs which was doped in a 5-pair Si δ-doping with a spacer GaAs-Si 2.5 nm thick. In both cases, low Rc values of ≤ (1-5) x 10-7 Ω-cm2 were achieved.
The Ge/Pd/n-GaAs Ohmic Contact Interface Studied by Backside Raman Spectroscopy
Authors: Watté J. , Silverans R.E. , Miinder H. , Palmstrøm C.J. , Florez L.T. , Van Hove M. , Borghs G. , Wuyts K. 
Published: April 2011

ABSTRACTThe Ge/Pd/n-GaAs ohmic contact structure constitutes a near-ideal model system to test the applicability of the different metal/GaAs ohmic contact models. After annealing, an atomically flat interface between the GaAs substrate and a regrown Ge layer is obtained. A main point of discussion is whether the ohmic conduction across this junction either occurs by an enhanced Ge-doping of the GaAs (regrown) substrate surface layers (the doping model), and/or by a degenerate As-doping ot the Ge overlayer (the heterojunction hypothesis). In order to examine the applicability of both models, a Raman study of this system is undertaken. By a backside thinning procedure, a metallization/60 nm GaAs structure is preserved, allowing for a backside optical analysis of the regrown Ge/GaAs interface region.
Effects of Pt and W2N/W Bottom Electrodes on Dielectric Properties of BaTiO3 Thin Films
Authors: Tae Kim Yong , Lee Chang Woo , Lee Jeong-gun 
Published: April 2011

ABSTRACTEffects of Pt and W2N/W bottom electrodes on dielectric properties of 1000 Å thick BaTiO3 thin film capacitors are studied. The tetragonality of BaTiO3 on W2N/W electrode is better than that of BaTiO3 on Pt electrode and leakage current of W2N/W/BaTiO3/Au capacitor is four orders of magnitude less than that of Pt/BaTiO3/Au capacitor. The excellent properties of W2N/W/BaTiO3/Au capacitor is ascribed to both of the tetragonal structure of WO3 formed at the interface of W/BaTiO3 and the diffusion barrier property of W2N preventing the interfacial reaction among bottom electrodes, BaTiO3, and Si.
Optical Properties of Metal Films and Their Silicides
Authors: Simard-Normandin M. , Naem A. , Saran M. 
Published: April 2011

ABSTRACTSilicides are used widely in microelectronic fabrication, yet there are very little data available regarding their optical constants at most wavelengths, and specifically at those of interest to G-line and I-line lithography. We have studied extensively the optical properties of Ti, Co, as metal films and as silicide films formed at various temperatures, and of CVD (chemical vapour deposition) W. Using spectroscopic ellipsometry at two angles of incidence, we have calculated the complex index of refraction N = (n, k) of these films every 10nm at 68 wavelengths between 230 and 900nm. These data are necessary to model accurately the reflectivity of wafers to study the effects of various thermal and surface treatments on silicide growth and to set exposure times for lithography. They also allow the use of reflectivity vs X as a non-contact method to map film thicknesses across wafers within the patterned devices themselves.
Non-Destructive Electrical Techniques as Means for Understanding the Basic Mechanisms of Electromigration
Authors: Scorzoni A. , De Munari I. , Stulens H. 
Published: April 2011

ABSTRACTIn this paper results of recently developed high resolution resistometric electromigration techniques will be described, with particular attention to the behaviour of narrow, near-bamboo metal lines. After a discussion on recent theoretical results published in the literature, a diffusion model correlating mechanical stress and electromigration will be adopted to describe experimental results of relative resistance change both during and after electromigration. The good agreement between experimental data and simulations must not hide that something must still be understood about the physical mechanism leading to resistance changes during electromigration experiments.
Reduction of Sn02 by A-Si1-XGeX
Authors: Edelman F. , Brener R. , Cytermann C. , Eizenberg M. , Weil R. , Beyer W. 
Published: April 2011

Thin films of amorphous Si1−xGex:H with x=0, 0.3, 0.6, and 1 were deposited by RF glow discharge at 200-250°C on SnO2/glass substrates. The tin dioxide was reduced by heat treatment at the temperature range of 400-600°C resulting in a layered structure of silicon oxide, tin suboxide and ß-Sn which formed at the a-Si1−xGex:H/SnO2 interface. A strong dependence of the extent of the reduction on the Ge content in the a-Si1−xGex:H films was found: at low temperatures (T≤475°C) the Si-rich layers were more reactive, whereas at T≥475°C the Ge-rich films totally reduced the SnO2. The interfacial reduction process was followed by a drop in the transparency and drastic changes in the sheet resistance of the a-Si1−xGex:H/SnO2 contacts.PACS: 61.43.Dq; 78.66; 82.65.-i; 82.65.Fr; 82.65.Yh
Single Crystal Epitaxial Ge Based Contacts to Gaas, and InGap
Authors: Dubey M. , Jones K.A. , Casas L.M. , Eckart D. , Pfeffer R.L. 
Published: April 2011

ABSTRACTNonalloyed, single crystal, oxide free Ge based ohmic contacts are almost atomically abrupt, have a smooth interface, and have the potential to be better understood. Ultra high vacuum electron beam evaporation is used to deposit a single crystal Ge film on GaAs and InGaP substrates. A large grain, highly oriented Au film or a poly crystalline Pd film with more randomly oriented grains was then deposited on the Ge. These films were characterized in the as grown condition by high resolution electron microscopy (HREM), double crystal x-ray diffraction (DXRD), Auger electron spectroscopy (AES), Rutherford back scattering (RBS) and scanning electron microscopy (SEM). The as deposited Ge film grown at 400°C on GaAs and at 350°C on InGaP are epitaxial with a smooth abrupt, oxide free interface. The highly oriented Au film deposited at 100°C had a smooth interface with the Ge with the orientation relationship (100)Au II (100)Ge and [001]Au II [011 ]Ge or [0-1 1 ]Ge.
Kinetics of Copper Grain Growth During Nitridation of Cu-Cr and Cu-Ti Thin Films by In Situ Tem
Authors: Atzmon Z. , Sharma R. , Russell S. W. , Mayer J.W. 
Published: April 2011

ABSTRACTCo-deposited Cu-Cr and Cu-Ti thin films were heated at various temperatures in an ammonia ambient in an environmental cell placed into the column of a transmission electron microscope (TEM). The reaction dynamics were observed in situ and recorded on a videotape using a TV camera with 1/30 second time resolution. Nitridation of chromium and titanium was accompanied by the nucleation and growth of copper particles starting at 370 and 580°C, respectively. It was found that in the Cu-Ti system at a temperatures regime of 370-400°C the growth rate behaves under a parabolic law; namely, the process is controlled by diffusion of Cu through the nitride matrix. However, for the Cu-Cr system at temperatures of 610-630°C two growth regimes were observed. In the initial growth stages, the surface reaction is rate-limiting, while for longer nitridation times, growth is diffusion-controlled.
Dry Etching of Ta-Si-N Diffusion Barrier Material in Cf4+02 Gas Mixtures
Authors: McLane G.F. , Casas L. , Reid J.S , KoIawa E. , Nicolet M-A. 
Published: April 2011

ABSTRACTSputtered Ta36Si14N50 amorphous diffusion barrier layers were reactive ion etched in CF4+02 plasmas. Etch rate varied with gas composition, with 15 percent 02 concentration producing maximum etch rate. Etch rates increased with both pressure and power. Etching proceeded only after an initial delay time which was dependent upon gas composition and applied power. The delay time was probably caused by the presence of a surface native oxide which must first be removed before etching can commence. Auger electron spectroscopy measurements showed the native oxide to be approximately 2 nm thick on as-grown samples, and indicate that near-surface stoichiometry is maintained on etched samples.
Comparison of Growth and Microstructure of Copper Films Deposited From Different Cu(Ii) Precursors
Authors: Goswami J. , Shivashankar S.A. , Raghunathan Lakshmi , Devi Anjana , Ramanathan K.V. 
Published: April 2011

ABSTRACTHigh quality copper thin films have been obtained by low pressure thermally-activated chemical vapour deposition from two different Cu(II) metalorganic precursors, (a) bis(dipivaloyl-methanato) Cu (II) or Cu(dpm)2 and (b) bis(t-butylaceto acetato)Cu(II) or Cu(tbaoac)2, the latter synthesised with a view to reducing the deposition temperature. A comparative study of the volatility and thermal stability of the two precursors, as well as of the growth and microstructure of copper films from these two precursors, is presented.While the threshold deposition temperature is significantly lower for Cu(tbaoac)2 compared to Cu(dpm)2, the growth rate is considerably higher with Cu(dpm)2-Films obtained from Cu(tbaoac)2 are denser and of lower resistivity at a given thickness compared to those from Cu(dpm)2, and are also smoother, exhibiting mirror-like reflectivity.
Polyimides and Copolyimides with Low Dielectric Constant, Low Moisture Absorption, and Low Coefficient of Thermal Expansion for use as Interlayer Dielectrics
Authors: Auman Brian C. 
Published: April 2011

ABSTRACTThe mechanical, thermal, electrical and moisture absorption properties of a series of fluorinated, highly rod-like polyimides and copolyimides are reported. Copolymerization with appropriate flexibilizing comonomers resulted in improved elongations versus those of the highly rod-like homopolymers while maintaining, to a large extent,the other desirable properties of the backbone. These materials are considered prime candidates for interlayer dielectric due to their excellent combination of properties.
Transmission Electron Microscopy of Mocvd Titanium Nitride Films
Authors: Itoh Toshio , Konno Toyohiko J. , Sinclair Robert , Raaijmakers Ivo J.M.M. , Roberts Bruce E. 
Published: April 2011

ABSTRACTThe effect of substrate temperature and process pressure on microstructure of MOCVD-TiN films deposited on oxidized Si substrates are studied by transmission electron microscopy (TEM). It is found that microstructure of MOCVD-TiN films distinctly changes with these deposition parameters and that the resistivity of the films is uniquely related to the microstructure. Films with the lowest resistivity (< 500 μohm-cm) show a uniform semi-columnar grain structure. Films with the highest resistivity (> 10,000 μohm-cm) show a uniform equi-axed micrograin structure. The other films exhibit a bi-layer structure: one layer of semi-columnar grains and the other of equiaxed micrograins. The thickness ratio of these layers changes with the deposition conditions and the resistivity is a unique function of the thickness of the semi-columnar grain layer.
Basic Science in Silica Glass Polishing
Authors: Tomozawa Minoru , Yang Kai , Li Hong , Murarka Shyam P. 
Published: April 2011

ABSTRACTWater entered into oxides when the oxides were indented with diamond in the presence of water or water vapor. Similar water entry is expected during silica glass polishing because of the high stress concentration on the glass surface in contact with small abrasive particles. Both chemical and mechanical properties of silica glasses change with water content. Polishing rate of silica in oil-based slurry with diamond abrasive increased with water content in the silica. Since oil has no chemical reactivity with silica, mechanical property degradation with water incorporation must be responsible for the fast polishing rate of the water-containing samples. A plausible mechanism of the polishing of silica is, therefore, water entry into silica under stress and mechanical removal of the altered layer. In the presence of water this process repeats itself.
High Power and High Frequency Silicon Carbide Devices
Authors: Palmour John W. , Carter C. H. , Weitzel C. E. , Nordquist K. J. 
Published: April 2011

ABSTRACTThe breakdown electric field of 4H-SiC as a function of doping was measured using pn junction rectifiers, with maximum voltages of 1130 V being achieved. 4H-SiC vertical power MOSFET structures have shown specific on-resistances of 33 mΩ-cm2 for devices capable of blocking 150 V. A current density of 100 A/cm2 was achieved at a drain voltage of 3.3 V. Thyristors fabricated in SiC have also shown blocking voltages of 160 V and 100 A/cm2 at 3.0 V. High temperature operation was measured, with the power MOSFETs operating to 300°C, and the thyristors operating to 500°C.Submicron 6H- and 4H-SiC MESFETs have shown good I-V characteristics to Vd= 40 V, with an Idss of 200–300 mA/mm. The maximum operating frequencies (fmax) achieved for 6H-SiC MESFETs is 13.8 GHz, with small-signal power gains of 9.8 dB and 2.9 dB at 5 GHz and 10 GHz, respectively. 4H-SiC MESFETs have demonstrated an RF output power density of 2.8 W/mm at 1.8 GHz. This is the highest power density ever reported for SiC and is 2–3 times higher than reported for comparable GaAs devices.
Comparison of Microwave ECR and RF Plasmas for Dry Etching of Single Crystal 6H-SiC
Authors: Flemish J. R. , Xie K. , Buchwald W. , Casas L. , Zhao J. H. , McLane G. , Dubey M. 
Published: April 2011

ABSTRACTElectron cyclotron resonance (ECR) plasma etching of single crystal 6H-SiC has been investigated using a CF4/O2 gas mixture and compared to conventional reactive ion etching (RIE) in a radio frequency (13.56 MHz) reactor. The use of ECR results in higher etch rates, lower levels of bias and smoother etched surfaces than rf-RIE. ECR etch rates exceeding 100 nm/min have been obtained at a substrate bias of-100 V. Etch rate and surface morphology have been studied as a function of pressure, bias and power. Auger electron spectroscopy shows that ECR etching leaves no residues unlike rf-RIE which leaves residues containing Al, F, O and C. The current-voltage and capacitance-voltage measurements of Schottky diodes show that there is far less damage induced by ECR etching compared to rf-RIE.
Characterization of MS, MiS, and Mos Contacts to Type IIB Diamond by Capacitance-Voltage and Current-Volt Age
Authors: Wynands Henry A. , Hartsell M. L. , Fox Bradley A. 
Published: April 2011

ABSTRACTThree types of electrical contacts on natural type lib single crystal diamonds have been studied by current-voltage (IV) and capacitance-voltage (CV) measurements. Vertical structures were fabricated with the metal-diamond (MS), metal-undoped diamond-doped diamond (MiS), or metal-SiO2-doped diamond (MOS) contacts and ohmic contacts on the opposite face of the diamond. The MS contact was rectifying and both the MiS and MOS were blocking contacts. While very high leakage currents were measured on the MiS structure in forward bias (MO6times the reverse bias), an accumulation region was observed in the MiS CV data. The uncompensated acceptor concentration values calculated from the CV data were in good agreement for different structures fabricated on the same samples and with the secondary ion mass spectroscopy (SIMS) measurements of the bulk boron concentration. Extreme stretch out was observed in the CV of the MiS and MOS due to interface traps. The density of interface traps was estimated to be in the 1012 cm-2 eV-1 range for these structures.
Diamond Growth Rates and Quality: Dependence on Gas Phase Composition
Authors: Cassidy William D. , Evans Edward A. , Wang Yaxin , Angus John C. , Bachmann Peter K. , Hagemann Hans-Jurgen , Leers Dieter , Wiechert Detlef U. 
Published: April 2011

ABSTRACTDiamond growth rates and quality were studied as a function of source gas composition and correlated with position on the ternary C-H-O diagram. The chemical potentials of carbon and oxygen change dramatically on either side of the H2-CO tie line, leading to large differences in the equilibrium distribution of species. These differences are reflected in the species flux reaching the diamond surface, and hence in the quality and growth rate of the diamond. In situ microbalance measurements in a hot-filament reactor show that the reaction rate is independent of the CO concentration, but decreases with increasing O2. Quality, as measured by Raman spectroscopy, increases as the C/C+O ratio in the source gases is reduced to approach the critical value of 0.5. The stability of the filaments to decarburizing and oxidation are correlated with the carbon and oxygen chemical potentials and hence to the position on the C-H-O diagram. A preliminary ternary diagram for the C-H-F system is presented.