bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Lamp Pulses on the Oxygen - Precipitation - Gettering of Cr in Czochralski Grown Si
Authors: Chabane-Sari N-E. , Krieger-Kaddour S. , Vinante C. , Barbier D. 
Published: March 2011

ABSTRACTExperiments on the intrinsic gettering of Cr in p-type Czochralski-grown Si including lamp pulse annealings have been carried out. Transmission Electron Microscopy observations of both oxide and metallic precipitates on cross-sectional specimens, as well as quantitative results about the electrically active metal depth-profiles, using Deep Level Transient Spectroscopy measurements, are presented. We have observed that a lamp pulse (1200 °C/5 s) applied prior to a three-step gettering cycle produced a strong retardation of the oxygen precipitation, and consequently an inhibition of the Cr bulk precipitation during the nucleation step. Besides, it was observed that the Cr-precipitates formed in the bulk during the oxygen nucleation step were highly unstable upon a post-gettering 2–4 s lamp pulse at 1000 °C, whereas the same lamp pulse did not produce a significant re-dissolution of Cr-precipitates formed during the oxide precipitate growth step. The reversibility of the intrinsic gettering of Cr upon a post-gettering lamp pulse thus critically depends on the oxide precipitate growth rate during the gettering process.
Damage to Crystalline Silicon Following Implantation by Low Energy Silicon Ions
Authors: Levine Y. , Herbots N. , Dunham S. 
Published: March 2011

ABSTRACTA new approach to investigate low energy defect formation and annealing in a crystal is developed, based on experimental observations of the total number of interstitials. The model is applied to damage in crystalline silicon caused by low energy implantation of Si-atoms during 40eV implants at 300°Kand 685°K. The model has two versions, analytical and computational, and includes two kinds of diffusing species, self-interstitials and vacancies, their interaction, surface motion of the growing crystal, and a constant source of defects. The source was calculated using a modified TRIM code (TRJMCSR). The focal point of the analysis is the number of interstitials per ion dose surviving at the end of the deposition time (damage to dose ratio or DDR, which is found to be an informative quantity and can be calculated for more sophisticated models including precipitation.
Passivation of Ion-Beam-Induced Defects at and Around the Si-SiO2 Interface by Ion Beam Hydrogenation
Authors: Kar S. , Srikanth K. , Ashok S. 
Published: March 2011

ABSTRACTElectronic defects were introduced at and around the Si-SiO2 interface by exposing thermally-oxidized silicon samples to a 16 keV Si ion beam in an ion implanter. The oxide thickness was 350 Å. Following Si self-implantation, hydrogenation was carried out at room temperature by a 400 eV hydrogen ion beam from a Kaufman source. Experimental results obtained from the admittance-voltage-frequency measurements of the metal-oxide-silicon structures indicated significant passivation of the ion-beam-induced defects.
B+, P+, AS+ and Si+ Ion Implantation Induced Defects in Silicon Studied by a Variable-Energy Positron Beam
Authors: Sugiura Jun , Ogasavara Makoto , Uedono Akira , Vei Long , Tanigava Shoichiro 
Published: March 2011

ABSTRACTVacancy type defects introduced by As+, P+, Si+ and B+ ion implantations into Si (100) single crystals were studied by a variable-energy positron beam. Depth distributions of the defects were obtained from measurements of Doppler broadening profiles of the positron annihilation as a function of incident positron energy. The results showed that this technique is sensitive not only to a vacancy type defect but to formation of amorphous regions. The defects introduced by lower doses were identified as vacancy clusters from isochronal annealing experiments. By higher doses such as 5×1014 /cm2, amorphous layers were formed for 150KeV As+, 150KeV P+, and 200KeV Si+ ions, and it was not formed for 80KeV B+ by the dose of 5×1015 /cm2. These results are consistent with the calculated critical doses. In the case of B+, pre-amorphous formation was observed with higher ion beam current over 5mA and a dose of 5×1015 /cm2.
Noncontact Characterization for Ultraviolet Light Irradiation Effect on Si-SiO2 Interface
Authors: Katayama K. , Shimura F. 
Published: March 2011

ABSTRACTThe effect of ultraviolet (UV) irradiation on the minority-carrier surface recombination lifetime (τs) in silicon wafers with native or thermal oxide was studied with a noncontact laser/microwave photoconductance (LM-PC) technique. The τs greatly increases in samples with native oxide after the irradiation. The dominant factor for the τs change can be negative charges created by photo-injected electrons in the surface area. On the other hand, the irradiation decreases τs in silicon with thermal oxide. The τs decrease is due to the generation of carrier recombination centers with an energy level around 0.2eV at the Si-SiO2 interface.
Dry Etching of Indium Phosphide
Authors: Bond P. , Sengupta P. , Orrman-Rossiter Kevin G. , Reeves G. K. , Paterson P. J. K. 
Published: March 2011

ABSTRACTIndium Phosphide (InP) based multilayer structures are becoming increasingly important in the semiconductor industry with optoelectronic applications being the main growth area. Mesa type structures with finely controlled width and etch angle, often form the building blocks for many of these photonic devices. Traditional wet etching techniques have often proved to be inadequate for the required anisotropie removal of material. This paper presents the results of etching semi-insulating InP (100) using a combination of an Argon ion beam and a reactive gas, CCl2F2 (Freon 12). It was found that the etch rate was enhanced by increasing the ion energy and by the addition of CCl2F2. Auger electron spectroscopy revealed that the increased etch rate was accompanied by an increase in the surface indium concentration and at low ion beam energies carbon build-up retarded the etch rate. The optimum etch angle to fabricate 3μm waveguides was found to be 22° to the surface normal, however Schottky contacts to these structures were unsuccessful.
Simultaneous Implant Activation and Isolation Formation in GaAs in a Single High-Temperature Anneal
Authors: Ko Kei-Yu , Chen S. , Braunstein G. , Zheng L.-R. , Lee S.-T. 
Published: March 2011

ABSTRACTUsing void-related compensation in Al-implanted GaAs, high-resistivity isolation regions that are thermally stable to high temperatures (> 700 °C) are demonstrated. The high-temperature thermal stability of the isolation regions allows the simplification of device processing in which a single high-temperature anneal (e.g., at 900 °C) can be used to activate the implant dopants in the device-active regions, and simultaneously to convert the Al-implanted regions highly resistive for electrical isolation. Other advantages of using void-related isolation will also be discussed.
Electronic Levels and Properties of the Selfinterstitials in Irradiated Silicon
Authors: Abdullin Kh. A. , Mukashev B. N. , Tamendarov M. F. , Tashenov T. B. 
Published: March 2011

ABSTRACTDLTS studies of electronic states and properties of the selfinterstitial in α-irradiated p-Si and n-Si are performed. The injection-enhanced annealing is observed for two traps E2 (Ec -0.39 eV) and El (Ec -0.26 eV) in p-Si. The annealing of E2 and E1 are simultaneous with the growth of hole traps connected with vacancy (V), Ci and Ali. It is concluded that the observed electronic levels belonq to different charge states of silicon selfinterstitial. The conclusion is confirmed by the differences of cross sections of the formation of Ali and Ci, by the influence of the zero and reverse bias conditions on the introduction rate and optical annealing of the E2 state in p-Si as well as by DLTS spectra of n-Si.
The Growth of Effective Potential Barrier Height in Au/ (100) n-GaP Contact Induced by Phosphorous Ion Implantation
Authors: Ivashchenko Anatol I. , Kopanskaya F.Ya. , Solomonov A. I. , Tarchenko V. P. 
Published: March 2011

ABSTRACTThe effect of phosphorous ion implantation and/or rapid thermal treatment on the behaviour of Schottky barrier elect-rophysical characteristics formed on the plane (100) of n-GaP epitaxial layer is discussed. Even though the implantation and post implantation rapid annealing lead to the generation of deep recombination centers in the bulk, the dominant mechanism of current transport across the barrier structure becomes thermo-ionic - like in initial samples. The analysis of the behaviour of forward current-voltage characteristics, steady state capacitance-voltage characteristics and DLTS data allow to conclude that the obtained reduction of forward current after ion im- plactation can be attributed to an increase of effective potenia! barrier height.
Vacancy-Type Defects in Proton-Bombarded InP
Authors: Ascheron C. , Krause R. , Polity A. , Sobotta H. , Riede V. 
Published: March 2011

ABSTRACTIn proton-bombarded InP single crystals the fluence-dependent production of vacancy-type radiation defects and their annealing behaviour are studied. The results are interpreted using measurements of the total defect concentration, the carrier concentration and the infrared absorption.
Processing of Refractory Ores in a Microwave Induced “Cold” Plasma
Authors: Bullard D.E. , Lynch D.C. 
Published: March 2011

ABSTRACTA Microwave Induced Plasma has been used to investigate the processing of metallurgically significant refractory oxides in a non-equilibrium or “cold” plasma. The main emphasis of this work has centered on the reduction of TiO2 in a hydrogen plasma. The plasma was maintained using microwave energy (2.45 GHz) in a single mode resonant cavity. The reaction was monitored for volatile species with a quadrupole mass spectrometer, while the extent of reaction was determined by an external standard X-Ray diffraction technique. The effect of process variables (absorbed power by the plasma, chamber pressure, and time) on the extent of reaction was investigated. Hydrogen reduction in a plasma has produced up to 60% conversion of TiO2 to Ti2O3 in 11 minutes with the sample on a grounded support rod, while only an 8% conversion is observed for a sample on an insulated support rod. Sample temperatures were below 735 K for most plasma conditions, based upon thermodynamic considerations.
Characterization of an ECR Microwave Plasma Etching System
Authors: Jin Ming , Kao Kwan C. 
Published: March 2011

ABSTRACTAn ECR microwave plasma etching system and an alternating bias voltage source with variable frequencies ( 10kHz to 10 MHz ) have been built for the study of the effects of the substrate bias on the submicron feature etching. A quadrupole mass spectrometer was used for the end-point monitoring and the plasma chemistry analysis. A Langmuir probe was used to characterize the etching plasma. The system can generate plasmas with densities ranging from 1×1015m−3 to 5×1016m−3 corresponding to gas pressures from 1×10−4 torr to 6×10−3torr at a fairly low microwave power. This condition results in a stable electron temperature. The magnetic field profile can be adjusted to obtain a constant plasma density of 2.8×1016m−3 and an electron temperature in kTe of 4 eV to 5 eV. The plasma beam is of 75mm in diameter with the ion current intensity fluctuation of about ±5% at the etching position for the gas pressures ranging from 4×10−4 torr to 3×10−3 torr at an absorbed power of 70Watts. The plasma density, the electron temperature, the breakdown power, and the sustaining power have been studied as functions of gas pressure in order to optimize the etching performance.
The Effect of Particle Size on Microwave Heated Carbon and the Subsequent Crystallite Growth
Authors: Lorenson Claude P. , Patterson Mark C.L. , Risto Gail , Kimber Robert 
Published: March 2011

ABSTRACTThe dielectric properties of carbon imply that heating with microwave energy should not be significant at elevated temperatures. It has been demonstrated, however, that temperatures in excess of 1900°C can be achieved with low powers. The effect of particle size on the heating rate will be presented and a heat absorption mechanism is postulated to explain the high temperatures observed.Under controlled conditions, conventional and microwave heating has been used to observe growth of the carbon crystallite size up to a temperature of 1400°C. Under these conditions, no enhanced crystal growth was observed for microwave heating.
Theory of Sublinear Power Dependence of Microwave Heating in Some Ceramic Materials
Authors: Kenkre V. M. , Kus M. , Katz J. D. 
Published: March 2011

ABSTRACTA sublinear dependence of the microwave heating rate on the incident microwave power implying a saturation effect appears to have been observed recently. We present simple model calculations to address this observation on the basis of an idea of spatial confinement of the absorbing charges in grain boundary regions. Two natural lengths exist in this model: the spatial extent of the confining region, and the maximum distance an absorbing charge travels under the combined action of damping and of the oscillating microwave field. We suggest that a mismatch of these lengths results in the observed saturation, more generally, in the observed decrease in absorption efficiency.
Microwave Absorption by Lossy Ceramic Materials
Authors: Campisi Isidoro E. , Summers Lynda K. , Finger Keith E. , Johnson Anne M. 
Published: March 2011

ABSTRACTMicrowave energy generated by the electron beam in the superconducting cavities of the Continuous Electron Beam Accelerator Facility (CEBAF) is absorbed by special loads fabricated with a novel lossy ceramic material (AIN-glassy carbon) developed especially for this application. Strict environmental constraints (ultra-high vacuum compatibility, operation at 2 K, brazeability, etc.) are imposed on the materials which can be used. Several other ceramics were sintered with AIN and various minority conductive powders to obtain the desired electrical properties according to the ‘artificial dielectric’ model. Dielectric permittivity data and results of low temperature measurements are reported.
Pulsed Microwave Processing of High-TC Superconducting Films
Authors: James R. B. , Alvarez R. A. , Stamper A. K. , Bao X. J. , Schlesinger T. E. , Ginley D. S. , McCarty K. F. , Friedmann T. A. , Stulen R. H. 
Published: March 2011

ABSTRACTWe have used 2.0-μsec microwave pulses at a frequency of 2.856 GHz to rapidly heat thin amorphous yttrium-barium-copper-oxide (YBCO) films deposited onto silicon substrates. The samples were irradiated inside a WR-284 waveguide by single-pass TE10 pulses in a traveling wave geometry. X-ray diffractometry studies show that an amorphous-to-crystalline phase transition occurs for incident pulse powers exceeding about 6 MW, in which case the amorphous YBCO layer is converted to Y2BaCuO5. Microscopy of the irradiated film reveals that the phase transition is brought about by melting of the YBCO precursor film and crystallization of the molten layer upon solidification. Time-resolved in situ experiments of the microwave reflectivity (R) and transmissivity (T) show that there is an abrupt change in R for microwave pulse powers exceeding the melt threshold, so that measurements of R and T can be used to monitor the onset of surface melting.
Metallorganic- and Microwave-Processing of Monolithic and Polyphasic Ceramics
Authors: Willert-Porada M. 
Published: March 2011

ABSTRACTA method for microstructural modelling of ceramic materials utilising precursor compounds and heating by microwave radiation to introduce a second phase as well as to control grain growth is described. The precursor compounds are introduced into the ceramic material by infiltration of a porous compact or by impregnating a classical powder with the precursor prior to compaction. Microwave radiation is used for decomposition of the precursor and for sintering. Decomposition rate controlled pyrolysis of the precursor is only possible by microwave heating. The resulting microwave processed ceramics display a finer and in some cases more bimodal microstructure as compared to conventionally processed samples with the same density.
Metallorganic and Microwave Processing of Cermets
Authors: Willert-Porada M. , Gerdes T. , Vodegel S. 
Published: March 2011

ABSTRACTPreliminary results are decribed on synthesis of ceramic-metal composites with a functional gradient material character utilizing infiltration of a porous metallic matrix with ceramic precursors and thermal processing by MW-heating. Infiltration of the metal matrix with a ceramic precursor facilitates bonding between metal and ceramic. By repeated infiltration and decomposition, complete filling of the pores with a ceramic phase is achieved.Using SiC as MW absorbing material in a sandwich-like configuration, heating of the metal-ceramic composite in a strong MW field is possible. Temperatures of apr. 1000°C were achieved with this method.
Microwave Processing of Polymers - An Overview
Authors: Lewis David A. 
Published: March 2011

ABSTRACTThis paper surveys some of the recent research into the microwave processing of polymers. The mechanism of coupling of the radiation with polymers is described and a historical perspective is presented on the development of this technology from the 1960's when the processing of rubber was first initiated, to current research in high performance materials and composites. The controversial area of microwave effects on processing is also discussed.
Reaction Sintering of Ceramic Materials by Microwave Heating
Authors: Boch Ph. , Lequeux N. , Piluso P. 
Published: March 2011

ABSTRACTMicrowave heating was used to reaction sinter Al2O3 + SiO2 and Al2O3 + TiO2 powder mixtures to prepare mullite and aluminum titanate ceramics, respectively. In comparison with conventional heating, microwave heating leads to a decrease in the temperatures of treatment of 50 to 100°C.
Microwave Sintering of Multilayer Ceramic Capacitors
Authors: Lauf R. J. , Holcombe C. E. , Hamby C. 
Published: March 2011

ABSTRACTMultilayer ceramic capacitors of several compositions (both Z5U and NPO types) were sintered in air in both conventional and microwave furnaces. Several casketing and insulation techniques were used to improve temperature uniformity and minimize dopant losses. Zirconia and yttria are suitable packing materials as either powders or fibers. After sintering, the packing material remains friable and can be recycled. The presence of metallization layers did not interfere with the microwave process and no arcing was observed at surfaces where the internal electrodes emerged. In some runs, however, local thermal runaway was observed, which could severely decrease process yields and must be eliminated in a commercial process.
Thermal Runaway and its Control in Microwave Heated Ceramics
Authors: Kriegsmann Gregory A. 
Published: March 2011

ABSTRACTThe heating of a ceramic slab under TEM illumination is modeled and analyzed in the small Biot number regime. The temperature distribution is almost spatially uniform in this limit and its evolution in time is governed by a first order nonlinear amplitude equation. This equation admits a time independent solution which is a multivalued function of the microwave power. The dynamics of the heating process are deduced, from the amplitude equation and the multivalued response, and are dependent upon the microwave power and initial conditions. The results of this analysis give a plausible explanation of certain difficulties arising in sintering experiments, such as thermal runaway. A simple control process is presented and analyzed which mitigates against these deleterious effects. Abbreviated parameter studies are performed showing trends in the controlled heating process.A quasi-three-dimensional problem modeling the heating process of a thin cylindrical sample in a waveguide applicator is also presented. For certain excitations the physical phenomenon deduced from this model and the required control process are the same as those obtained for the slab. For other excitations there is a strong spatial structure along the axis of the sample. For a certain choice of parameters the middle portion of the sample is at an elevated temperature while the remaining portion is at a much lower temperature. This phenomenon may be useful in joining applications.
Automatic Control to Prevent Thermal Runaway During Microwave Joining of Ceramics
Authors: Beale Guy O. , Arteaga Francisco J. 
Published: March 2011

ABSTRACTA temperature control system is designed and simulated for microwave joining of ceramics. The objective is to develop a control system for reliable, high quality joints to be produced on a variety of ceramics. The described procedure permits the derivation of a closed-loop configuration for controlling temperature. The ceramics (alumina) heating model equation is linearized around an operating point and represented as a transfer function. Conditions for closed-loop stability with any linearized model are presented and mathematically proven. A computer simulation is implemented for the closed-loop control and numerical integration is used for solving the non-linear heating equations. Results are very good and show that the temperature can be regulated to a set point value and thermal runaway in the ceramics can be prevented.
Microwave Joining of Silicon Carbide Using Several Different Approaches
Authors: Ahmad Iftikhar , Silberglitt Richard , Black W. Murray , Sa'Adaldin Hussamaldin S. , Katz Joel D. 
Published: March 2011

ABSTRACTMicrowave joining of sintered silicon carbide, both to itself and reaction bonded silicon carbide, has been accomplished in a single mode rectangular resonant cavity. Several approaches using different interlayer materials were employed to join sintered silicon carbide. Effective joining of reaction bonded silicon carbide to itself and sintered silicon carbide was accomplished without the use of any interlayer material in the single mode resonant cavity as well as in a multi-mode oven. Specimens cut from 0.95 cm diameter rods were joined in the single mode cavity, whereas a variety of arbitrary shapes and larger specimens (of reaction bonded silicon carbide) were joined in the multi-mode oven.
Batch Process for Microwave Sintering of Si3N4
Authors: Patterson M.C.L. , Apte P.S. , Kimber R.M. , Roy R. 
Published: March 2011

ABSTRACTA method for sintering silicon nitride using microwave energy at 2.45 GHz is described. Sintering takes place in air, in times of between 30 and 120 minutes and has been scaled up to give isothermal conditions over a batch size of 150 mm diameter by 200 mm in height and weighs approximately 1.0 kg. Additions of 5% alumina and 5% yttria result in a sintered product density of approximately 97% of theoretical, with a density variation better than:±0.5% throughout the batch.It has been estimated that a load of 7.0 kg can be conventionally sintered using a 12 hour cycle and an energy consumption of 19.7 kWh/kg. In contrast with microwave energy, a batch of 540 g can be sintered in 120 minutes with an energy consumption of approximately 3.1 kWh/kg. This results in a possible energy savings of up to 78% for microwave heating.
Microwave Processing of Ceramics - An Overview
Authors: Sutton Willard H. 
Published: March 2011

ABSTRACTDuring the past decade, many exploratory studies and experiments have been performed on the microwave heating and processing of ceramics and composite materials. Much of this effort was stimulated by the unique and potential benefits that microwave energy can provide over conventional processing methods. While microwave processing of ceramics is still in an early developmental stage, there are many areas yet to be explored, challenges to be met, and economic and commercial payoffs to be substantiated.Since the first MRS International Symposium on Microwave Processing in 1988, interest in this field has grown and many new developments have occurred. The purpose of this paper is to highlight some of the recent advances, to discuss the current state-of-the-art, and to suggest some future directions.