bluuebunny/crossref_metadata_2025_split huggingface dataset:
Point Defects in a Directly-Bonded Wafer, and its Comparison with the Bonded Soi Wafers
Authors: Usami Akira , Kaneko Keisuke , Ito Akira , Ishigami Shun-ichiro , Wada Takao 
Published: March 2011

ABSTRACT<Directly-bonded wafers were characterized using capacitance-voltage (C-V) and deep level transient spectroscopy (DLTS) measurements. We also studied silicon on insulator (SOI) wafers with different interfacial oxide thicknesses. In the active layers of the directly bonded wafer, two dominant electron traps (Ec-0.16eV, Ec-0.24eV) were observed at 23 μμμμm from the bonded interface. Both trap densities are almost constant (about 2 × 1011cm−3) at distances larger than about 10 μm. In the substrate, the density of the shallower electron trap increases (about 8 × 1011 cm−3) within about 20 μm from the interface, while the other trap concentration is almost constant and nearly equal to that in the active layers. No trap was observed near the wafer backside. These traps were also observed in the bonded SO1 wafers. Both the trap concentrations depend on the thickness of the bonded interfacial oxide. The shallower trap concentration increases with increasing oxide thickness, and the deeper one decreases.
Evaluation of Silicon Photodiode as X and Gamma-Ray Detector at Room Temperature
Authors: Cimpoca V. , Caragheorgheopol G.H. , Lazarovici D. , Lazarovici C. , Ruscu R. 
Published: March 2011

ABSTRACTA silicon photodiode 10 sqmm area designed for 0,45 A/W and maximum sensitivity at 900 μm, was tested as X and gamma-ray detector in the 6-122 keV range. The simple structure, good manufacturing and passivating for a NIP photodiode (6 KΩcm,p- type material) gives a yield of 20% from batch with suitable characteristics for low energy X and gamma-ray detection. A cheap nuclear detector for technical measurements results. Evaluation and analysis of parameters in X and gamma detection is made for these silicon structures; they are mounted on TO-8 holders without entrance lenses. The applications proposed namely the composition test of alloys (with known matrix) by X-ray fluorescence analysis and in radiation safety field (absorbed dose survey), ex. in radiological clinics defectoscopic laboratories or in front of video displays.
Analysis of HgI2 And PbI2 Crystals and Detectors by Particle-Induced X-Ray Emission (PIXE) and Ion Backscattering Spectroscopy (IBS)
Authors: Bench G. S. , ANTOLAK A. J. , MORSE D. H. , HEIKKINEN D. W. , PONTAU A. E. , JAMES R. B. , DAVID D. C. , BURGER A. , VAN DEN BERG L. 
Published: March 2011

ABSTRACTThe Ion Micro-Analysis Group (IMAG) in Livermore conducts quantitative trace elemental analysis with PIXE and depth profiling with IBS using an MeV ion microbeam. The system has the capability to produce two-dimensional trace element and IBS images. PIXE analyses have been conducted on HgI2 and PbI2 crystals and detector materials in order to identify and quantify near surface trace contaminants. IBS measurements have been conducted to investigate elemental depth distributions in various materials. The results of measurements on several different samples are reported and a discussion of factors affecting quantitative in vacuo microanalysis of these materials is presented.
In-Situ Temperature Control for Rtp Via Thermal Expansion Measurement
Authors: Peuse Bruce , Rosekrans Allan 
Published: March 2011

ABSTRACTA new method of temperature control for rapid thermal processing of silicon wafers is presented whereby in-situ wafer temperature is determined by measurement of wafer thermal expansion via an optical micrometer mechanism. The expansion measurement technique and its implementation into a rapid thermal processing system for temperature control are described. Preliminary data show the wafer to wafer temperature repeatability to be 1% (3-σ) using this technique.
In-Situ Temperature Monitoring in Rtp by Acoustical Techniques
Authors: Degertekin F.L. , Pei J. , LEE Y.J. , Khuri-Yakub B.T. , Saraswat K.C. 
Published: March 2011

ABSTRACTA new technique utilizing the high sensitivity of acoustic wave velocity to temperature is used to measure the wafer temperature in RTP. Acoustic energy is coupled to a Lamb wave mode in the wafer using the quartz support pins already present in most rapid thermal processors. The tips of the pins are sharpened to have point contact with the wafer and acoustic transducers are bonded to the other end to excite and detect acoustic waves. By measuring the pin-to-pin time of flight of Lamb waves, it is possible to monitor the wafer temperature in-situ in the 20 - 1000°C range with ±5°C accuracy. Increasing SNR to 50dB by spring loading the pins and using better electronics, it is possible to improve this figure to ±1°C. Also a modified system with multiple spring loaded pins is constructed and wafer temperature mapping is performed using tomographic reconstruction techniques. The resulting images are in good agreement with thermocouple readings and can be used for temperature control and rapid thermal processor design.
Rapid Thermal Processing: Status, Problems and Options After the First 25 Years
Authors: Roozeboom Fred 
Published: March 2011

ABSTRACTThis paper reviews the current status, problems and options in RTP system and process design. Some commercial systems will be discussed along with some improvements that can still be made in temperature reproducibility, process control and yield. This includes some recent developments in temperature reproducibility by compensated emissivity control.Uniformity issues regarding temperature and process gas hydrodynamics are highlighted in relation to reactor design. Especially in CVD applications, where radiative heat transfer may not longer dominate convective and conductive heat transfer, modeling and visualization of gas flow patterns are becoming increasingly important. Here, reactor design should be such that a laminar flow regime is reached without turbulence and without chemical memory effects upon switching to other gas compositions. Some flow visualization results are illustrated.Some new options for micro- and nanocrystallization reactions are presented before we conclude with a technology roadmap to the 1-Gbit era.
An Extensible Software Design Applied to Rapid Thermal Processing
Authors: Dankoski Paul , Gyugyi Paul , Franklin Gene 
Published: March 2011

ABSTRACTThe next five to ten years will show a dramatic increase in the number of sensors and actuators in use. Several advances in technology, namely integrated sensors, fast reliable communications, and powerful computers, are making such changes possible. Coordinating the complex interactions of multiple sensors and control settings can be too confusing for an ad-hoc approach. Applying modern model-based control theory to multi-input/multi-output systems has the potential of improving the yield and throughput in a computer integrated manufacturing environment.Our expectation is that as more sensors and actuators become available, it will be important to handle internal communications between processing subsystems in a uniform manner to allow for incremental expansions to the processing equipment. Because of the wide assortment of physical sensors available for control equipment, an architecture is presented which attempts to unify the communications and control in a multiprocessor environment. The focus of this paper will be to explain one method of controlling a Rapid Thermal Multiprocessing chamber and how it is designed to handle future growth.The implementation and experimentation are being performed on the Rapid Thermal Multiprocessor (RTM) at the Center for Integrated Systems (CIS) at Stanford University.
Combined Simulation and Measurement Study of Temperature Uniformity in Rapid Thermal Processing
Authors: Lin Yur-Tsai , Subrahmanyan Ravi , Sitaram A. R. 
Published: March 2011

ABSTRACTModeling and simulation of rapid thermal processing has been studied extensively in the past. This work presents the results of a combined simulation and measurement study of a commercial multilamp RTP chamber. The simulations were used to estimate the contributions of different geometrical, material, process, and physical effects on temperature uniformity. The physical effects considered in the simulations included radiation, thermal conduction, transient effects during ramp up and cool down and the effects of patterns on the wafer surface. The effects were corroborated by direct temperature measurements using thermocouple embedded wafers, and the results were used to reliably calculate stress effects. The stress distributions were determined analytically in cases without surface films on the wafer. In the case of wafers with surface films, stress distributions were calculated based on thermal strains. This study allows us to concentrate efforts on increasing temperature uniformity to those areas where the greatest benefits in terms of yield and film uniformity can be obtained.
Rta Implant Monitor: Does it Tell the Truth?
Authors: Lojek B. 
Published: March 2011

ABSTRACTThe measurement of the sheet resistance of Arsenic implanted layers is almost exclusively used for the monitoring of temperature nonuniformity of RTP equipment. However, as is shown in this contribution this technique relies on several averaging processes and a satisfactory uniformity of sheet resistance achieved on the implant monitor does not mean that the same performance will be achieved on the wafer with different optical properties. The sheet resistance uniformity is not the only the function of the processing temperature but also the function of the processing parameters such as annealing time, rate of heating and cooling, intensity of radiation and its spectral variation as well as function of the optical properties ofthe processed material. Impact of the substrate on the achieved results and processing dependence are discussed.
Reduced Thermal Budget Borophosphosilicate Glass (BPSG) Fusion and Implant Activation Using Rapid Thermal Annealing and Steam Reflow
Authors: Thar R.P.S. , Gonzalez F. , Hawthorne R. , Ward V. , Jeng N. 
Published: March 2011

ABSTRACTHighly dense next generation dynamic random access memory (DRAM) devices impose severe restrictions on the times, temperatures and atmospheres of all thermal process steps following the sourcedrain implantation. BPSG reflow and source-drain implant activation are two of the process steps that contribute significantly towards enhanced overall thermal budget during the fabrication of DRAM devices.In this paper, we present the results of an optimized thermal budget process using a combination of steam reflow and rapid thermal annealing (RTA). We demonstrate that this approach produces better reflow characteristics than the best RTA or reflow cycle alone. The processes will be compared on pchannel CMOS devices and the differences in various electrical characteristics will be highlighted. The results of BPSG reflow and dopant outdiffusion will be presented. Experimentally obtained data on junction depth from SIMS analysis will be correlated with corresponding RTA simulation results.
High Quality Ultra-Thin Tunneling N2O Oxides Fabricated by Rtp
Authors: Yoon G. W. , Joshi A. B. , Kim J. , Kwong D. L. 
Published: March 2011

ABSTRACTIn this paper, a detailed reliability investigation is presented for ultra-thin tunneling (∼50 Å) oxides grown in N2O ambient using rapid thermal processing (RTP). These N2Oss-oxides are compared with oxides of identical thickness grown in O2 ambient by RTP. The reliability investigations include time-dependent dielectric breakdown as well as stress-induced leakage current in MOS capacitors with these gate dielectrics. Results show that ultra-thin N2O-oxides show much improved reliability as compared to oxide grown in O2 ambient.
Fabrication of Ultra-Shallow P+-N and N+-P Junctions by Diffusion From Selectively Deposited, Ion-Implanted and In-Situ Doped Si0.7Ge0.3
Authors: Grider D.T. , ÖztÜrk M.C. , Wortman J.J. , Harris G.S. , Maher D.M. 
Published: March 2011

ABSTRACTSelectively deposited Si0.7Ge0.3 has been investigated as a potential diffusion source for fabricating ultra-shallow junctions in Si. Rapid thermal chemical vapor deposition (RTCVD) was used to selectively deposit Si0.7Ge0.3 on Si using SiH2C12, GeH4, and H2. Both ionimplanted and in-situ doped Si0.7Ge0.3 were considered as a diffusion source for fabricating ultra-shallow junctions. In-situ doping was achieved with B2H6 and PH3 for p-type and n-type doping, respectively. Boron and phosphorus diffusion in ion-implanted Si0.7Ge0.3 was investigated and modeled using SSUPREM4. Diffusion from implanted and in-situ doped Si0.7Ge0.3 in Si was also studied and modeled. Boron diffusivities in Si0.7Ge0.3 were found to be approximately 10 times greater than in Si, while phosphorus diffusivities were over 100 times greater in Si0.7Ge0.3. The faster dopant diffusivities in Si0.7Ge0.3 allow high surface concentration, abrupt diffusion profiles to be formed in Si. Gated, p-n junction diodes with junction depths as shallow as 140Å were fabricated and tested to study the quality of the diffusions from Si0.7Ge0.3.
Fabrication of High Quality Mos Devices for Application in Hazardous Environments Based on Rtp Gate Dielectrics With in Situ Rtcvd of Polysilicon Gates
Authors: Fröschle B. , Bruemmer H.P. , Lang W. , Neumeier K. , Ramm P. 
Published: March 2011

ABSTRACTProcess modules for MOS gate fabrication were developed which can be completed subsequently in one RTP reactor: atmospheric process sequences for gate oxides and oxynitrides as well as low pressure chemical vapor deposition of polysilicon (RTCVD). Prior to the Rapid Thermal Oxidation (RTO), the wafers were treated with a Rapid Thermal Cleaning process (RTC) in H2/Ar ambient. After the desoxidation step the RTO was done in O2/H2/Ar followed by an anneal (RTA) for the gate oxide or a nitridation in NH3 (RTN) and reoxidation for the oxynitrides, respectively. The polysilicon gate electrode was fabricated either by RTCVD in situ or in a conventional furnace reactor. The two-step RTCVD process resulted in a very good thickness uniformity for the polysilicon layers of 3% (3mm from the edge). The influence of the process variations on breakdown field, fixed oxide charge, interface state density, flatband voltage, and threshold voltage of the different types of gate dielectrics was investigated. The charges and voltages were determined by LF-HF CV measurements. In order to characterize the radiation tolerance of electronic devices, radiation induced flatband and threshold voltage shifts as well as the build up of interface charges were determined. The irradiation was performed at a Co - 60 gamma source. Breakdown fields in the range of 19 MV/cm, interface state densities of less than 109 eV−2cm−2, and radiation induced threshold voltage shifts below 0.1 V after 1.5 Mrad(Si) were obtained.
Improved Passivation of Silicon Solar Cells Using Combined Low-Energy Hydrogen Implantation and Optical Processing
Authors: Sopori Bhushan L. 
Published: March 2011

ABSTRACTAn improved technique for impurity/defect passivation of silicon solar cells is described. A low-energy hydrogen implantation is performed from the back side of solar cells to produce a deep hydrogen diffusion. The deep diffusion is believed to be caused by the formation of a mobile hydrogen-vacancy (H-V) complex. Next, a layer of Al is deposited on the hydrogenated side and an Optical Processing (OP) step is performed. The OP step accomplishes several objectives that include formation of an ohmic contact, dissociation of H-V complexes to release hydrogen that can participate in further passivation, and dissolution and regrowth of the highly defected surface layer.
Improving The Barrier Properties of Nickel. Chrome and Nichrome Films on Silicon
Authors: Nowicki Ronald S. , Arias Louie , Rau Chris , Motamedi Ahmad , Harris David W. , Baumann Scott 
Published: March 2011

ABSTRACTA new technique for improving the diffusion barrier properties of thin, thermallyevaporated nickel, chromium and nichrome films on silicon is described. In this technique, known as “Rapid Thermal Annealing” (RTA), profound differences in the diffusion barrier properties of the films annealed in ammonia ambient at 550-750°C, in comparison to films annealed only in vacuum, were observed. The films annealed in ammonia retained their integrity while the films annealed in vacuum showed diffusion of the silicon into the metal overlayer throughout the entire thickness of the metal in some cases. The film sheet resistance increase for the latter was consistent with the formation of the metal silicide. The possibility of extending this technique to electroplated films used in integrated and hybrid device fabrication is being studied.
A Low Frequency Remote Plasma Rapid Thermal CVD System with Face Down Electrostatic Clamp Wafer Holder
Authors: Bonfim Marlio J. C. , Swart Jacobus W. , Velasco Cristian E. M. , Okura Juscelino H. , Verdonck Patrick B. 
Published: March 2011

ABSTRACTA multiprocess CVD system with the following main features is designed and constructed: the wafer holder is made of a Si wafer with diameter larger than the process wafers. This larger holder produces a better temperature uniformity on the process wafer. A good thermal contact between holder and process wafer is obtained by an electrostatic clamp. The holder supports the process wafer facing down. A remote plasma is produced in a small chamber inside the process chamber. The 100 KHz RF frequency keeps the system very simple and cheap while still reasonable ionization is achieved. SiO2 films were deposited using SiH4 and O2 with and without remote plasma of O2. At low temperatures and 1.5 Torr, process activation energies of about 0.9 and 0.3 eV were obtained respectively.
Modelling the Dielectric Growth on Silicon Produced in a Nitrous Oxide Rtp Environment
Authors: Harrison H Barry , Dimitrijev Sima , Sweatman Denis , Parker Joanna , Preston Stephanie 
Published: March 2011

ABSTRACTThe results of measurements of the physical properties of the dielectric grown on various orientations and surface doping concentration on silicon in an N2O environment are presented. We use this data to produce a model that predicts the dielectric thickness as a function of time and temperature.
Computer Simulation of Chain Molecule-Inorganic Interphases: Chromatographic Stationary Phases and Rigid Rod Self-Assembled Monolayers
Authors: Klatte S. J. , Zhang Z. , Beck T. L. 
Published: March 2011

AbstractMolecular dynamics simulations of alkane chains chemically tethered to silica surfaces are presented. The system was modeled after the stationary phases of chromatographic columns. The interphase properties were computed as functions of chain length, surface bonding density, and temperature. At densities appropriate for chromatography, the chains undergo a gradual transition with increasing temperature from a glassy state to a liquid-like state. The simulations are consistent with extensive experimental data including neutron scattering, NMR, IR, and EPR methods. The implications for chromatographic retention are discussed. In a second series of studies, we explored driving forces for observed ordering on the solid surface in terms of the various components of the chain-chain and chain-surface forces. Interfacial z profiles are sensitive functions of each of the forces. Finally, we present preliminary Monte Carlo results on origins of tilt behavior in self assembled monolayers of rigid chain species on metal surfaces.
Surface-Enhanced Raman Scattering as an In-Situ Probe of Polyimide/Silver Interphases
Authors: Young J. T. , Boerio F. J. 
Published: March 2011

AbstractThe molecular structure of interphases formed between thin films of the polyamic acid of pyromellitic dianhydride (PMDA) and oxydianiline (ODA) and silver substrates that were pretreated with m-aminothiophenol (m-ATP) was determined using surface enhanced Raman scattering (SERS) and X-ray photoelectron spectroscopy (XPS). It was found that m-ATP adsorbed dissociatively onto silver substrates through the thiol groups. When thin films of the polyamic acid of PMDA/ODA were spin-coated onto the silver substrates treated with m-ATP, an interphase that was only a few angstroms in thickness was formed in which acid groups of the polyamic acid and amino groups of the m-ATP combined to form ammonium carboxylate species. The bulk of the polyamic acid films was cured to polyimide by immersion in mixtures of acetic anhydride and pyridine or triethylamine but ammonium carboxylate species inhibited curing in the interphase.
The Use of a Single-Fiber Fragmentation Test to Study Environmental Durability of Interfaces/Interphases Between Epoxy and a Glass Fiber
Authors: Schuute Carol L. , McDonough Walter , Shioya Masatoshi , Hunston Donald L. 
Published: March 2011

AbstractThis work examines the usefulness of the single-fiber fragmentation test in studying the durability of fiber/matrix interfaces/interphases. This test measures the critical length/diameter ratio (L/D) of the fiber fragments formed in the test and relates this length to the interface's strength, or ability to transfer load. In the work reported here, we immersed samples of epoxy containing a single-glass fiber - that was previously sized with an epoxy-compatible coating - in either 65 or 75 °C water and tested after different times of exposure. In general, this ratio increased as a function of time of exposure to water. During exposure at 75 °C, the fibers' L/D in the samples did not increase significantly until after the sample reached its “apparent” equilibrium content of water ∼ (3.0 wt%). Because there was no significant measurable change in the tensile modulus between wet and dry samples, we cannot attribute these differences in L/D to changes in the resin's properties due to plasticizing by water. A small percentage of samples exposed at 65 °C did not show a significant increase in L/D, and in these cases the moisture produced a marked roughening of the fiber surface along the fiber/matrix interface. One possible explanation is that the attack by moisture degrades the interface, thus reducing its strength with a corresponding increase in the L/D. To varying degrees, however, the attack by moisture also degrades the E-glass fiber. This attack by moisture roughened the surfaces of the fibers and increased the distribution and/or size of the critical flaws, thus reducing both the strength of the fiber and the L/D. Based on our preliminary results, it appears that the singlefiber test has the potential to be useful for studying the durability of the resin/matrix interface providing that the influence of the environmental agent on all of the components of the model composite: resin, fiber, and interface/phase, is considered.
Density Functional Calculations on the Metal-Polymer Interfaces
Authors: Selmani A. , Ouhlal A. , Yelon A. 
Published: March 2011

AbstractBonding of chromium to the polyimide, PMDA-ODA, surface is still subject to debate. In an attempt to clarify this problem, we have performed density functional theory calculations on a model molecule, phthalimide, which contains the most reactive functionalities of the polyimide PMDA part. Considering only the low spin case, we find that chromium bonds preferentially to the phenyl ring. However, when we release the spin polarisation and optimise the structure, we find that the absolute stable configuration is that of chromium in a quintet state at a carbonyl group. The energy difference is 0.30 eV. The complete optimised structures are determined. The infrared spectrum have been calculated for phthalimide and compared to experimental spectra. The agreement is excellent. A vibrational analysis for the Cr/phthalimide system, in both configurations (Cr on C=O and Cr on phenyl), in their stable spin states, is presented.