bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amorphous Hydrogenated Semiconductors
Authors: Reimer Jeffrey A. 
Published: March 2011

AbstractSemiconducting thin films are produced in plasma and CVD reactors and are commercially useful materials because of a ubiquitous presence of hydrogen, a low density of defects, and electro-optical properties which vary systematically with composition.However, little is known about how variations in fundamental growth parameters produce concomitant changes in film properties, particularly hydrogen incorporation.The reason for this gap in knowledge derives partly from the lack of adequate structural probes of disordered materials.In recent years nuclear magnetic resonance spectroscopy (NMR) has emerged as a powerful probe of the microstructure of amorphous semiconductors.I will discuss recent developments in the application of NMR to studies of amorphous hydrogenated semiconductors, and interpret these results in terms of the chemistry and physics of the growth process.
Hydrogenated Amorphous Carbon(a-C:H), An Overview.
Authors: Meyerson Bernard S. 
Published: March 2011

AbstractOver the past several years, numerous new materials have been prepared by the glow discharge decomposition of gaseous species.Among these, a material with extraordinary though as yet unfulfilled potential is hydrogenated amorphous carbon(a-C:H).As a metastable state between the two naturally occurring carbons, graphite and diamond, a-C:H can display a wide range of phyical characteristics.Film optical and electronic properties are a strong function of deposition parameters, where 2.l>Eopt >0.9eV.and 1016 >ρ>106Ω-cm., for films deposited between 75 and 375C.Occasionally referred to as “diamond-like”, such films can be extraordinarily hard and virtually impervious to chemical attack.The interrelation of film structure on the atomic level and macroscopic film properties will be discussed, with emphasis on the current controversy over whether such material is indeed diamond-like in its microscopic ordering.
Plasma Mode Trench Etching with Direct Hydrocarbon Injection
Authors: Leeke Steven D. , Liu David Kuan Yu , McVittie James P. 
Published: March 2011

AbstractPlanar plasma etching of silicon for fabrication of deep trenches has been studied using the method of factorial design.A highly anisotropic etching profile with a slight positive slope is obtained using SF6, C2C1F5, and CH4 in the low energy plasma etch mode.The anisotropy is attributed to the polymerization of CH4 molecules with the active species in the plasma.The polymer is removed preferentially in the vertical direction by energetic ions from the plasma, leaving the polymer layer on the side wall to inhibit lateral etching of silicon.Good uniformity across the wafer and smooth trench surfaces are obtained with this process.Trench depths of greater than 3μm with less than 0.24μm of undercut are observed.Etch rate measurements were made and found to be greater than 1000 angstroms/minute.Selectivity over the oxide mask is greater than 15:1.By using factorial design to statistically characterize this process, the effects of interactions between various process parameters are studied.Optimal etching conditions are obtained from the interaction terms for the process parameters.The ability to etch deep trenches with smooth surfaces, low damage, low linewidth degredation, and high selectivity make this process useful for many applications in VLSI devices.
Optical and Compositional Properties of a-C:H and BN Films
Authors: Pouch John J. , Alterovitz Samuel A. , Warner Joseph D. 
Published: March 2011

AbstractThe amorphous dielectrics a-C:H and BN were deposited on III–V semiconductors.Optical band gaps as high as 3 eV were measured for a-C:H generated by C4 H10 plasmas; a comparison was made with bad gaps obtained from films prepared by CH4 glow discharges.The ion beam deposited BN films exhibited amorphous behavior with band gaps on the order of 5 eV.Film compositions were studied by Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS).The optical properties were characterized by ellipsometry, UV/VIS absorptiofr, and IR reflection and transmission.Etching rates of a-C:H subjected to O2 discharges were determined.
Monte Carlo Modeling of Ion Transport Througe RF Glow Discharge Sheaths
Authors: Fisher Donald A. , Thompson Brian E. , Sawin Herbert H. 
Published: March 2011

AbstractThe transport of ions through a rf-plasma sheath was simulated using a Monte Carlo method to determine the distribution of ion bombardment energy and impingement angle.Several types of ion-molecule interactions were tested to determine their effect on the distributions: elastic hard-sphere scattering, elastic potential-field interactions (based upon reported literature values obtained by drift tube measures), and charge transfer.The type of elastic scattering does not significantly change the angular distributions; however, the scattering cross-sections changes as a function of ion energy (or sheath E/P) for the potential-field interactions.The fraction of collisions giving charge exchange makes a large difference in the simulated directionality as well as a factor of two difference in the average bombardment energy.
RIE Plasma and ETCH Mechanisms
Authors: Keller John H. 
Published: March 2011

AbstractThree independent models are presented: One for determining the plasma density and target sheath voltage, one for silicon etching using CF4plus O2, and one for RIE etching of silicon dioxide.In most dry etching techniques the target and plasma voltages play a large role.In this paper, the dc and rf mechanisms which determine the plasma density, and thus the target voltage, are presented.The mechanisms used are: 1) secondary electron ionization in the sheath, 2) secondary electron ionization in the plasma, 3) ionization by tertiary electrons, 4) I2R heating of the plasma electrons, and 5) sheath heating of plasma electrons.An equivalent circuit for an rf discharge is presented, and the relationship between the plasma voltage and target sheath voltage are discussed.The mechanisms used to model silicon etching include chemical etching, ion enhanced etching and diffusion of reactive species.Laser induced fluorescence data from G.S.Selwyn will be discussed.These data show spatial resolution of a reactive species in an RIE plasma and show the diffusion effects.The ion-enhanced etching effect for SiO2, shows a much stronger voltage dependence than that for Si, which is almost independent of voltage.Data from G.Fortuno show that the voltage dependence for SiO2 is similar to that of sputtering.The mechanisms used to model SiO2 etching include the work by G.Fortuno (1985) and that by B.N.Chapman and V.J.Minkiewicz (1978).
A Plasma Chemistry and Surface Model for the Deposition of a–Si:H from RF Glow Discharges: A Study of Hydrogen Content
Authors: Kushner Mark J. 
Published: March 2011

AbstractAn integrated electron kinetics, plasma chemistry, and surface deposition model has been developed to study the relationship between film characteristics and plasma parameters in the plasma enhanced chemical vapor deposition (PECVD) of amorphous hydrogenated silicon (a–Si:H) in low pressure parallel plate RF discharges.The integrated model consists of a Monte-Carlo simulation for the electron distribution function in the RF discharge, a time and spatially dependent plasma chemistry model, and a model for the surface deposition process.The surface model consists of an accounting of the surface density of adsorbed species, and the fractional distribution of various types of bonds (e.g.Si–Si, Si–H, Si–.) in the film.The calculated distribution of radicals in silane discharges will first be discussed.The computed hydrogen content and deposition rates of a-Si:H films from silane and disilane discharges are next discussed and compared to experiment.The dependence of hydrogen content on Rf power and substrate temperature is calculated and agrees well with experiment.Mechanisms are proposed to explain these dependencies.
Deposition of Dielectric Films by Remote Plasma Enhanced CVD
Authors: Lucovsky G. , Tsu D. V. , Markunas R. J. 
Published: March 2011

AbstractWe describe a plasma enhanced chemical vapor deposition process (PECVD) developed for the low temperature deposition of thin films of silicon oxides, nitrides and oxynitrides.The process, designated as remote PECVD (RPECVD), differs from conventional PECVD in two ways; (a) not all of the process gases are subjected to plasma excitation; and (b) the deposition is done outside of the plasma region.We include an empirical model of the deposition process chemistry and discuss the use of infrared spectroscopy (IR) and Auger electron spectroscopy (AES) to characterize the local atomic structure of the deposited films.
Deposition of Titanilum Nitride Thin Films by Plasma Enhanced CVD and Reactive Sputtering
Authors: Gleason E. F. , Hess D. W. 
Published: March 2011

AbstractTitanium nitride films were deposited from TiCl4 /NH3 mixtures in a rf glow discharge.The deposition was carried o t at pressures between 0.1 and 0.7 Torr, RF powers of 0.1 to 1.1 watt/cm2, and temperatures between 400°C and 600°C.The films deposited at 600°C had low chlorine content and resistivities in the range of 100 to 200 μΩ-cm.Films deposited at temperatures below 500°C contained large amounts of chlorine (> 15 at %) and showed poor electrical properties.The films were further characterized by Rutherford Backscattering Spectroscopy (RBS), X-ray Photoelectron Spectroscopy (XPS), and Auger Electron Spectroscopy (AES).The effect of plasma parameters on the deposition rate and film properties is discussed.Comparisons to films prepared by reactive sputtering of titanium in a nitrogen atmosphere are presented.
Deposition of Aluminum Nitride Films Using RF Reactive Sputtering
Authors: Kumar N. , Pourrezaei K. , De Maria R. J. , Singh B. 
Published: March 2011

AbstractRF reactive sputtering of aluminum in argon-nitrogen mixture has been used to deposit basal oriented aluminum nitride films at temperatures lower than 200°C.X-ray diffraction studies of films deposited in 40–60% nitrogen show very high degree of crystallinity.A characteristic step-like decrease in target induced dc bias and the deposition rate (at a constant rf power level) is observed when the nitrogen content is increased above about 20%.The plot of target bias vs.nitrogen content shows a typical hysteresis loop which decreases in size at higher power levels, thus indicating nitride formation at the target surface.Glow discharge mass spectrometry was used to monitor the ions arriving at the substrate.There is a dramatic decrease in Al+ ion current when the nitrogen percentage in the gas mixture is increased above 20%.
Etching and Surface Modification of Polyimide in O2 -SF6 Plasmas
Authors: Kogoma M. , Turban G. 
Published: March 2011

AbstractEtch rates of Kapton H polyimide film in SF6 - O2 plasmas (0.25 torr) were studied as a function of the input gas mixture, the excitation frequency (25 kHz -450 kHz; 13.56 MHz) and the biasing mode.The treated surface was examined by X P S, SEM and contact angle measurement.The ion and neutral species of the plasma were sampled and analyzed by mass spectrometry.A proposed kinetic analysis of the etching mechanism is in good agreement with the experimental data.
Quartz Crystal Microbalance Studies of the Plasma-Assisted Etching of Polyimide and Tungsten Thin Films
Authors: Fracassi F. , Coburn J. W. 
Published: March 2011

AbstractThe etching of polyimide thin films and tungsten thin films has been studied as a function of bias voltage using two quartz crystal microbalances (QCM) installed in a low pressure 13.56 MHz rf plasma system.One of the QCM's is biased (rf bias was used for the polyimide films; de bias was used for the tungsten films) and the other QCM is unbiased.In this way, the influence of energetic positive ion bombardment on etching can be studied.The etching of polyimide is studied in CF4-O2 glow discharges whereas CF4-H2 gas mixtures were used in the etching of tungsten.In the tungsten etching studies, the surfaces were vacuum-transferred to an Auger electron spectrometer for surface analysis.
Thermal and Ion-Assisted Reactions of Al0.3Ga0.7as with Molecular Chlorine
Authors: Balooch M. , Olander D. R. , Siekhaus W. J. 
Published: March 2011

AbstractReaction of Al0 3Ga0 7As with molecular chlorine was studied with and without simultaneous bombardment by energetic argon ions.The reaction products signals were measured as functions of surface temperature.For the purely thermal reactions, the main products below 600 K were AlCl3, AsCl3 and GaCl3.The etching rates were two orders of magnitude lower than those of pure GaAs.With simultaneous ion bombardment, the reaction product signal of AsCl3 at room temperature increased by almost a factor of four over the corresponding thermal reaction signal.The comparable enhancement factor for pure GaAs was ∼6.
Dynamics of Electron and Photon Stimulated Desorption
Authors: Walkup R. E. , Avouris Ph. 
Published: March 2011

AbstractWe discuss specific examples of desorption due to electron or photon bombardment of solids, in which the repulsive interactions that result in particle expulsion can be clearly identified.A particularly interesting example is the desorption of positive ions from alkali-halides.Classical trajectory calculations are used to provide a picture of the atomic-scale motion during desorption.The results show that dynamic distortions of the lattice play a crucial role in the desorption process.
The Interaction of CF3+ and CH4+ With SiO2 Surfaces
Authors: Thomson D. J. , Helms C. R. 
Published: March 2011

AbstractIn this paper we present experimental results and a theoretical model for the interaction of CF3+ and CH4+ with SiO2 surfaces.A comparision of the sputter rates for CF3+ and CH4+ with a molecular sputtering model shows that there is a chemical enhacment in the etch rate for CF3+ but not for CH4+.By comparing the Si (LVV) AES spectra for these two surfaces we have determined that the enhancement is due to the strong Si-F bond promoting the formation of volatile carbon containing compounds.
Magnetron Enhanced Reactive Ion Etching in a Hexode System
Authors: Bell Scott , Bril Thijs 
Published: March 2011

AbstractA method of forming a uniform magnetic field in a modified hexode type etch system is described.Experimental results of etching Si, SiO2 and photoresist with NF3 are presented.The magnetic field effectively increases the ion flux and decreases the energy of the ions bombarding the cathode.It was found that adding a magnetic field increases the etchrate of Si for the conditions studied, but for SiO2 and photoresist, the decreased ion bombardment energy leads to lower etchrates under certain conditions.The resulting effect on selectivities is discussed.
Anisotropic Dry Etching of Aluminum Films Deposited on Topographic Steps
Authors: Maa Jer-Shen , Halon Bernard 
Published: March 2011

AbstractDuring the etching of aluminum film, if the film is deposited on a surface which contains sharp topological steps, and if the etching proceeds mainly along the vertical direction, it becomes very difficult to remove the remaining residue.Experimental results are discussed in terms of effects of native oxide film and polymer film formation.A simple model is proposed to reveal the residue formation process and to explain the problem encountered during the removal of the etched residue.
Plasma Assisted Oxidation of Si at Temperatures below 800°C
Authors: Williams C. K. , Reismanu A. 
Published: March 2011

AbstractA system for plasma assisted oxidation of Si at temperatures below 800°C is described.Oxides grown in this system have an unusual thickness versus time relationship.The first 110 nm of oxide exhibit a t1/2 dependence.Any additional growth shows a t1/3 dependence.Pressure, oxygen concentration, and rf power are all important parameters in determining the growth rate and uniformity of the oxide layers.Breakdown measurements on these oxide layers show that post oxidation annealing is necessary if these oxides are to compete with thermal oxides.The type of annealing is very important in determining the breakdown voltage.The results of various annealing procedures are described.The effects of heating the wafers independent of the heat generated by the plasma, and the frequency dependence of the growth are discussed.
RF and Microwave Plasma Deposition of Polymer Films: Effect of Frequency
Authors: Claude R. , Moisan M. , Wertheimer M. R. 
Published: March 2011

AbstractThe surface wave (SW) plasma technology is used to investigate possible frequency effects in the deposition kinetics of plasma polymers over the range 100–915 MHz.Hydrocarbon and fluorocarbon monomers are excited by a SW produced argon plasma, at a total pressure of 50 mTorr, under various monomer flows.Using Yasuda's normalization procedure, we have so far been unable to distinguish frequency dependent deposition in this high frequency (HF) regime.However, the present data indicate substantially (an order of magnitude) higher deposition rates than those reported by Gazicki and Yasuda for low frequencies.
Optical Diagnostic Studies in Plasmas and Plasma Processing
Authors: Donnelly V. M. 
Published: March 2011

AbstractOptical diagnostic probes have greatly increased our understanding of low pressure discharges used in etching and deposition processes for microelectronics fabrication.Optical emission induced by energetic electron impact excitation provides a qualitative determination of concentrations of a number of important atoms and small radicals.Rare-gas actinometry, combined with high resolution line-shape measurements can convert emission data into quantitative relative number densities, and provide information on mechanism of excited state formation.Emission from products of etching reactions gives insights into mechanisms and serves as an end-point indicator for many commercial processes.Laser induced fluorescence is a sensitive probe which is most useful for small radicals.Quantitative, relative ground-state number densities, internal energy distributions, translational energies and electric fields can be determined by this technique.When optical emission or laser induced fluorescence measurements are performed with spatial resolution and in-phase with respect to the applied field, additional insights are obtained on the dynamics of the discharge processes.Finally, infrared and visible-ultraviolet absorption spectroscopy can be used to measure absolute number densities.This technique also can provide spatial and temporal resolution.This paper reviews and compares the various optical techniques used in plasma diagnostics with particular emphasis on studies of low pressure radio frequency discharges used in etching and deposition of thin films.
Crystallization Behavior and Properties of Rapidly Solidified Ni-Mo-B Alloys
Authors: Wan C.C. 
Published: March 2011

ABSTRACTThe crystallization phenomena of certain ternary glass Ni-Mo-B alloys and their consolidated bulk properties, including age hardening effects after proper heat treatment, are investigated. Within the composition range studied, the glassy alloys crystallize by a two-stage process - first by forming a metastable microcrystalline structure of Ni solid solution at temperature around 490–530°C followed by boride precipitation at temperatures around 700–770°C. The boride, which is identified by x-ray diffraction as Mo2NiB2 , grows to submicron size after the alloys have been thermally treated at 1000°C and above for certain periods of time. Microstructural analysis shows borides isolated and well dispersed in Ni-Mo alloy matrix. Age hardening is achieved by precipitating the Ni/Mo intermetallic compound(s) in Ni-Mo matrix at an intermediate temperature of previously solutionized samples. Another characteristic of this group of alloys is the relatively high eutectic temperature, i.e. 1230°C and above. This will allow the alloys to be hot consolidated to full density by certain commercially available processes, such as hot isostatic pressing (HIP), while still maintaining the unique microstructure inherited from rapid solidification process. Hardness, hot hardness and hot tensile properties of some consolidated alloys are discussed.
Microstructural and Chemical Components of Ceramic-Metal Interfacial Fracture Energies
Authors: Cannon R. M. , Jayaram V. , Dalgleish B. J. , Fisher R. M. 
Published: March 2011

AbstractFailure of ceramic-metal interfaces induced by residual or applied stress is often brittle in nature although plastic strain in one or more bonding layers may add to the fracture energy for decohesion. Thus, the fracture toughness depends on chemical bonding across the interface, the plasticity and flow stress of the metal as well as other factors, arising from local internal stresses and the microstructure of the ceramic-metal couple, that cause crack tip branching, deflection, bridging, blunting or shielding. Electron microscopy and DCB testing of metal-glass systems provide insights into the relative importance of factors that determine the decohesion resistance.
Stresses in Adhesively Bonded Bi-Material Assemblies Used in Electronic Packaging
Authors: Suhir E. 
Published: March 2011

AbstractThe magnitude and the distribution of stresses in elongated adhesively bonded bi-material assemblies subjected to uniform heating or cooling are determined and discussed. The suggested approach enables one to evaluate the stresses in the assembly components themselves, as well as the shearing and normal (peeling) stresses in the interface, with consideration of the attachment compliance. The case of an epoxy bonded assembly is used to illustrate the developed theory.
Microstructural Observations and Mechanical Behavior of Pb-Sn Solder on Copper Plates
Authors: Frear Darrel , Grivas Dennis , Quan Lenora , Morris J. W. 
Published: March 2011

AbstractThe microstructure and mechanical properties of Pb-Sn solder joining Cu plates were studied. Yticrostructural observations were made on both the bulk Pb-Sn solder and on the interface between the solder and Cu plates. Pb-Sn solder has a two-phase microstructure in which the Pb-rich phase is the weaker. β-Sn precipitates in the Pb-rich phase were characterized in TEM. Intermetallic phases (Cu6Sn5and Cu3Sn) that form during the reaction of molten Pb-Sn solder with Cu were investigated. Solder joints were tested to fracture in both shear and tensile configurations. The mechanical properties and fracture surface characteristics are reported.
Impurities of Epoxy Novolac Resins and their Influence on the Reliability of Encapsulated Semiconductors.
Authors: Kanagawa Shuichi , Terada Yutaka 
Published: March 2011

AbstractImpurities, especially chemically bonded impurities, of o-cresol novolac epoxy resins and their influence on the moisture resistance and other properties of the epoxy molding compounds have been investigated to clarify the influence of impurities of epoxy resins on the reliability of encapsulated semiconductor. As a result, the existence of hydrolyzable chlorine and hydroxyl group-containing impurities has been confirmed, and it was found that the impurity such as a hydrolyzable chlorine causes undesirable influence on both the moisture resistance and electrical properties at high temperatures. It was also found that the impurity such as a hydroxyl group causes undesirable influence on the moisture resistance, and that the lower hydroxyl content gives the higher heat resistance as a result of an increase in the epoxy content.