bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comprehensive Analytic Model of Accumulation-Mode Mosfet's in Polysilicon Thin Films
Authors: Ahmed S. S. , Kim Dae M. 
Published: March 2011

ABSTRACTThe performance of MOSFET's fabricated in LPCVD polysilicon thin films and operating in accumulation mode is modeled analytically. The model quantitatively explains reported device characteristics. Specifically, measured temperature coefficient of current, drive and leakage current, transconductance, drain admittance and ON/OFF current ratio are described in terms of inherent structural and electronic properties of polysilicon. The role of grain boundary hydrogenation in effectino the device performance is highliohted and ouantified.
Addressing the Problems of Agglomeration, Surface Roughness and Crystal Imperfection in Soi Films
Authors: Ramesh S. , Martinez A. , Petruzzello J. , Baumgart H. , Arnold Emil 
Published: March 2011

ABSTRACTWe have designed and experimentally tested, under a wide variety of laser recrystallization conditions, a reliable encapsulation structure that prevents agglomeration and enables recrystallization of SOT films over a 100% wafer area. Our experiments indicate that the wetting characteristics of the structure can also improve the surface planarity of the recrystallized silicon. We also report a dramatic reduction in defect density and the non - occurrence of the characteristic branched subgrain boundary pattern under appropriate conditions of laser recrystallization.
Low Temperature Gate Dielectrics for Tft Applications
Authors: Jones B L , Meakin D B 
Published: March 2011

ABSTRACTA series of low temperature CVD films of oxide (VAPOX and LTO) and nitride (PECVD ∝-SixNy:H) have been compared and optimised for use as gate dielectrics for TFT on insulator technology. The method of investigation involves the fabrication of MIS capacitor structures using the deposited insulator on single crystal n+ Si. I-V and C-V analyses yield information of the interested electronic stability parameters which are compared for the various insulators.
Twin Stabilzed Planar Growth of Soi Films
Authors: Baumgart H. , Phillipp F. , Ramesh S. , Khan B. , Martinez A. , Arnold E. 
Published: March 2011

ABSTRACTThe microstructure of beam recrystallized silicon-on-insulator (SOI) films is strongly dependent on nucleation and growth processes during zone-melt propagation. In general, the recrystallization takes place along the (100) plane and in the <001> direction and in this case subgrain boundaries form the only major defects in the material. We have, however, identified stable growth regimes that produce predominantly twin boundaries, when the SOl films recrystallize with their surface parallel to the (110) planes. The twin formation process is attributed to growth twinning characteristic for f.c.c. and diamond structures. It has been established that the majority of these boundaries consist of coherent twins. In this manner (110) textured SOl films can be grown which contain almost entirely twin boundaries as structural defects. The crystallography of coherent twin boundaries in SOI films and their dependence on growth parameters is presented.
˂100˃ Single Crystal Soi Films Obtained on 4. In Wafers Using Halogen Lamps
Authors: Haond M. , Dutartre D. , Bensahel D. 
Published: March 2011

ABSTRACTBy using a halogen lamp recrystalization system, we show that a patterning of the underlying oxide of SOI structures allows a high yield of localization of the remaining defects generally encountered in zone melting recrystallization. The influence of the scan speed and grain orientation on the efficiency of the entrainment is investigated. Moreover, we show that a quasi-single crystal can be obtained if a combination of seeding and oxide patterning is used.
Microscopy of Thin Si Films During Lamp Zone Melting
Authors: Dutartre D. , Haond M. , Bensahel D. 
Published: March 2011

ABSTRACTThe melting and solidification fronts of thin Silicon On Insulator (SOI) films have been observed in-situ. The melting front does not advance continuously but by bursts. This so called “explosive melting” allows to explain the appearance of defects (such as voids and surface roughness) observed in the recrystallized film. The freezing front is observed in the case where a pattern for the entrainment of the defects has been etched in the underlying oxide: we show that the entrainment effect is due to the spatial modulation of the solidification front by the structure. Furthermore, the scan speed influences the morphology of the liquid/solid interface and the defect entrainment efficiency.
Compound Formation And Silicon Behavior In Titanium And Tantalum Layered Aluminum Films
Authors: Shen B. W. , Anthony J. M. , Chang P-H. , Keenan J. , Matyi R. , Tsai H. L. 
Published: March 2011

ABSTRACTThin film interaction in the material systems of titanium and tantalum-layered Al- 1% Si films has been studied using advanced material characterization techniques. Compound phase formation was analyzed based on results from X-ray diffraction analysis. Al3Ti was identified in the titanium-layered film after 450° C sintering. TaSi2 and unreacted Ta. however, were identified after the sintering. Silicon participated in the phase formation process by incorporating itself as a solute in the Al3Ti while transforming Ta into its silicide. This behavior is to be interpreted based on available ternary phase diagrams. Cross-sectional transmission electron microscopy results indicate that well defined layered films and columnar grains of aluminum were obtained which are believed to be the primary reasons for the observed electromigration improvement over the base metal.
Amorphous W-Zr Films As Diffusion Barriers Between Al And Si
Authors: So F. C. T. , Zhao X.-A. , Kolawa E. , Tandon J. L. , Zhu M. F. , Nicolet M-A. 
Published: March 2011

ABSTRACTCosputtered W70Zr30 and W40Zr60 films are investigated as diffusion barriers between Al and Si. W-Zr alloys of both compositions were determined by x-ray diffraction to crystallize at 900°C on Al2O3 substrates. On <111>Si the W-Zr alloy reacts with the substrate above 700°C, forming a uniform, polycrystal line layer of W and Zr suicides. Despite the high crystallization temperatures, an Al overlayer interacts with W-Zr and the Si substrate at ∼500°C. MeV He backscattering spectrometry, SEM and EDAX indicate that this reaction is laterally nonuniform with the formation of deep pits penetrating into the Si substrate. We believe this to be a consequence of fractures in the W-Zr layer induced by reaction with Al. Electrical measurements on shallow junction diodes with <Si>/W-Zr/Al contacts show that the device junctions were thermally stable after a 30 min annealing at 450°C but were all shorted after heat treatments at 500°C or above.
A Grazing Incidence X-Ray Study Of Interfacial Reactions In Al-Cu
Authors: Heald S. M. , Chen H. , Tranquada J. M. 
Published: March 2011

ABSTRACTThe Al-Cu system has been used to test the application of grazing incidence EXAFS and x-ray reflectivity measurements to interface systems. Both techniques have been found to be sensitive to compound formation and interdiffusion, and with further development of analysis procedures should be very useful complements to more traditional techniques.
Ion Beam Mixing of Alternate Layers Of Ni-Nb and Ni-Cr
Authors: Rai A. K. , Bhattacharya R. S. , Rashid M. H. , McCormick A. W. 
Published: March 2011

ABSTRACTAlternating layers of Ni and Nb with a total thickness of 1060Å, and Ni and Cr with a total thickness of 840Å were deposited by electron beam evaporation on silicon. The individual layer thicknesses were adjusted in such a way as to obtain 50/50 at% compositions of Ni-Nb and Ni-Cr; the thicknesses were around 100Å for Ni and 170Å for Nb, and 100Å of Ni and 110Å of Cr. The films were bombarded with 350 keV Cr+ions at a dose of 2 × 10 ions cm. RBS and TEM techniques were used to study the mixing and microstructure. Almost complete mixing and amorphization have been observed for the Ni-Nb system. Ni-Cr film has revealed very little mixing compared to Ni-Nb film and the microstructure remained polycrystalline. Sputter (rf) deposited Ni-Cr film also remained polycrystalline both before and after ion irradiation. The Ni-Cr System appears to be an exception to the structural difference rule for amorphous phase formation by ion irradiation.
Silicon Layers Grown on Patterned Substrates by Liquid Phase Epitaxy
Authors: Bauser E. , KÄss D. , Warth M. , Strunk H. P. 
Published: March 2011

ABSTRACTSingle-crystal silicon layers and doping multilayers have been grown by liquid phase qpitaxy on silicon substrates. The substrates were either partially masked by SiO2, with via holes of various shapes and sizes, or patterned with SiO2 stripes, or profiled with grooves and ridges. The via holes and grooves were just refilled, or they acted as seeding areas for lateral overgrowth of the oxidized wafer up to 100μm. The silicon layers, interfaces and heterointerfaces were free of defects. With appropriate growth conditions the surfaces and interfaces of the epitaxial Si were outstandingly planar.
Cross-Sectional TEM Study Of Phase Separation In Reaction Of Ni-Ta Films With GaAs
Authors: Lahav A. , Eizenberg M. , Komem Y. 
Published: March 2011

ABSTRACTThe reaction between Ni60Ta40 amorphous alloy and (001) GaAs was studied by cross-sectional transmission electron microscopy, Auger spectroscopy, and x-ray diffraction. At 400°C formation of Ni GaAs at the interface with GaAs was observed. After heat treatment at 600°C in vacuum a layered structure of TaAs/NiGa/GaAs has been formed. The NiGa layer has epitaxial relations to the GaAs substrate. The vertical phase separation can be explained by opposite diffusion directions of nickel and arsenic atoms.
Ir Laser Assisted Grading Of Mocvd GaAsp
Authors: Wiseman T. , Juang C. , Jones K. A. 
Published: March 2011

ABSTRACTWe hypothesize that a primary growth mechanism for the MOCVD growth of GaAsP is a series of surface catalyzed methane elimination reactions, and that they can be affected either thermally or photochemically by the absorption of light from a CO2 TEA laser tuned to an absorption maxima. Our preliminary results show that the laser dramatically alters the morphology and supresses the phosphorus incorporation rate when the laser is tuned to an absorption maxima for the AsH3, We interpret these results to indicate that, for the conditions used, the the primary effect of the laser is photochemical, and that the phosphorus incorporation can be increased by exciting PH3, instead of AsH3,. Once the growth mechanisms are better understood and the growth conditions are optimized GaAs1−xPx/GaAs1-yPy superlattices with atomically abrupt junctions should be able to be grown simply by turning the laser on and off.
Transmission Electron Microscope Study of Interfacial Reactions in Gold-Germanium Contact to Gallium Arsenide
Authors: Kim Taeil , Chung D.D.L. 
Published: March 2011

ABSTRACTThe structure of 500 Å Au/500 A Ge/500 Å Au/GaAs (100) was studied by transmission electron microscopy after annealing at 350 – 500°C. Annealing at 350 – 450°C caused the formation of AuGeAs with a (110) texture, but this phase disappeared after annealing at 500°C. The hexagonal a-AuGa (or AuGa) was formed after annealing at 400°C, such that (111)Au // (0001)a, and [110]AU // [1120]a and there was perfect lattice match between Au (i.e., Au-rich solid solution) and a-AuGa. After annealing at 450°C or above, a phase tentatively identified as the hexagonal Au3Ga was formed and Ge (i.e., Ge-rich solid solution) became epitaxial to (100) GaAs. Annealing at 400°C caused Au to change from no texture to a (110) texture.
Interfacial Structure of In/Pt/GaAs Heterojunction Ohmic Contacts
Authors: Marvin D. C. , Ives N. A. , Leung M. S. 
Published: March 2011

ABSTRACTGraded heterojunction InGaAs ohmic contacts to n-GaAs have been prepared which show improved electrical and morphological properties compared with other diffused contacts. The improvements result primarily from the use of a thin 400 A Pt layer between the 4000 Â In layer and the substrate to control the reaction of the In and the GaAs. A study of chemically etched samples using energy dispersive x-ray (EDX) analysis has revealed the formation of a smooth In Ga, As heterojunction interface. Evidence is also presented that the heterojunction regions are epitaxial. A smooth, uniform interface of this type is not formed in other diffused contact systems, such as In/GaAs and Ni/Au-Ge/GaAs.
Schottky Barrier and Electronic States at Silicide-Silicon Interfaces
Authors: Schmid P. E. , Liehr M. , Legoues F. K. , Ho P. S. 
Published: March 2011

ABSTRACTThis paper reviews the recent studies on Schottky barrier and interface states at silicide-silicon interfaces, with emphasis placed on the results obtained from the epitaxial Ni suicides. A model based on interfacial defect states has been proposed to account for the overall chemical correlation between the barrier height and the metal electronegativity. Measurements on the barrier heights of type A, B and C epitaxial Ni suicides show that these three interfaces can be formed with high degrees of perfection to yield a barrier of 0.78 eV. Similar interfaces formed under less ideal conditions or with impurity incorporation decrease the barrier to 0.66 eV. The density and distribution of the interface states measured by a capacitance spectroscopy method correlate well with the structural perfection of the single and mixed-phase interfaces. A consistent picture seems to have emerged suggesting that the barrier height at silicide-Si interfaces is formed as a result of Fermi level pinning by interfacial defect states which are controlled primarily by the degree of perfection of the interface instead of the specific epitaxy.
Deposition of Thin Insulating films by Plasma Enhanced CVD
Authors: Lucovsky G. , Richard P. D. , Tsu D. V. , Markunas R. J. 
Published: March 2011

ABSTRACTWe discuss a new low temperature process for the deposition of electronic quality thin films of silicon oxide and nitride. In contrast to conventional plasma enhanced chemical vapor deposition [PECVD], this process involves the remote excitation of one of the gas reactants followed by the extraction of the active species out of the plasma region where they react to generate precursor molecules. The precursors undergo a CVD reaction at a heated substrate to form the desired thin film. The process is called remote PECVD [RPECVD]. Insulators produced in this way show significant reductions in the incorporation of impurity groups such as SiH and SiOH relative to films grown by the PECVD process at the same substrate temperatures.
Structural Investigation of Ti-N Films
Authors: Asplund M. , Korhonen A. S. , Molarius J. M. , Nykänen E. , Sulonen M. S. 
Published: March 2011

ABSTRACTTi-N films were deposited by reactive ion plating on various substrates. The N/Ti-ratio was systematically varied in order to produce films of varying structure and properties from pure titanium to overstoichiometric TiN. Broad diffraction peaks typical of PVD Ti-N films were found. Metastable ct-titanium was observed over a wide range up to about 50 at. % N. No marked differences in the phase composition or in the crystallographic texture could be found in the films deposited on the various substrates. The hardness of the films was observed to increase with increasing nitrogen content, reaching a maximum around 35 – 40 at. % N corresponding to a mixed ε-Ti2N and δ-TiN structure. Extended annealing at 773 K did not result in any major phase transformations. After annealing at 1173 K, α-Ti could no longer be found in nitrogen-rich films. Also ε-Ti2 N transformed to δ-TiN after annealing at 1173 K for 2 h.
HCL Oxidation of High Dose Arsenic Implanted Silicon
Authors: Choi Seong Soo , Numan M. Z. , Finstad T. G. , Chu W. K. , Fathy D. 
Published: March 2011

ABSTRACTThermal oxidation of high dose arsenic implanted p-type <100> silicon has been performed in order to study arsenic snowplowing. Bubble pattern formation and local oxide bowing (mound) in relation to the arsenic concentration in silicon as well as an HC1 ambient have been observed for an oxidation temperature of 1050°C. Oxide peel off at an oxidation temperature of 950°C for an atmosphere with an HC1 ambient has been observed. In addition, an anomaly in the temperature dependence of the oxidation rate independent of an HC1 ambient has been found.
Structural Evaluation of Interfaces by Electron Diffraction
Authors: Sullivan Tim D. , Ast Dieter G. 
Published: March 2011

ABSTRACTA method for extracting quantitative information from weak diffraction features at or near matrix reflections is described. The technique requires an accurate knowledge of the fall-off of the matrix reflection. This fall-off was studied both experimentally and theoretically for a wide range of coherence conditions in the microscope. Subtraction of this matrix contribution from the total intensity of an [004] reflection from a E=13 (001) twist boundary shows that the streak arises from local as well as from long range interference effects. The latter contribution varies with spatial coherence length which depends on the condenser setting of the microscope.
Strain Mapping in InGaAsP Epitaxial Films by An X-Ray Diffraction Technique
Authors: Chaudhuri Jharna , Mayo William E. , Weissmann Sigmund 
Published: March 2011

ABSTRACTA new x-ray diffraction method is developed to determine the full elastic strain tensor and its distribution about a strain center in single crystal materials. It is based on the recently developed Computer Aided Rocking Curve Analyzer and is particularly well suited for analysis of thin film structures common to electronic materials. This technique will be described in detail, and its application in measuring the non-uniform strains in InGaAsP epitaxial film on InP substrate will be presented. Also, possibility of using this method to measure the uniformity of film thickness will be discussed.
The Effects of Dopants and Crystal Perfection on the Chemical Vapor Deposition of Tungsten on Silicon by Silicon Reduction of Tungsten Hexafluoride
Authors: Green M. L. , Ali Y. S. , Davidson B. A. , Feldman L. C. , Nakahara S. 
Published: March 2011

ABSTRACTThe use of CVD W as a diffusion barrier between Al and Si is becoming widespread. The initial stage of the deposition involves the Si reduction of WF6 according to the following reaction:The reaction is thought to be self-limiting, since once a sufficiently thick W film forms, WF6 and Si are no longer able to be in contact. We have studied the effects of implanted dopant and damage on the rate of this reaction and the thickness of the self-limiting W film. To study the mechanism of W film growth, Si wafers were implanted with As, P or Sb. These wafers were either left in the as-implanted state (amorphized surface layer) or were annealed to drive-in the implant and recrystallize the Si. The reactivity with WF6 of these wafers, as well as unimplanted Si wafers, was then studied as a function of temperature between 210° C and 700° C. Si-WF6 reactivity is shown to have a strong temperature dependence, with maximum reactivity occuring at 340 °C, at which temperature a 960A thick film of W can form. Enhanced diffusion of Si through the growing W film is thought to be the mechanism responsible for thick film growth. At higher temperatures, thinner films form, due to the cessation of enhanced diffusion. Lower temperature films are also thinner, probably due to a nucleation barrier, not a kinetic barrier, to growth. Implantation lowers the temperature of the onset of enhanced reactivity between Si and WF6, when the wafers are reacted in the as-implanted state.
The Effects of Dopants on Surface-Energy-Driven Secondary Grain Growth in Ultrathin Si Films
Authors: Kim H.-J. , Thompson C. V. 
Published: March 2011

ABSTRACTSecondary or abnormal grain growth has been observed in ultrathin films of silicon (<120nm) that were heavily doped with phosphorous or arsenic. This grain growth leads to grains which are much larger than the film thickness (>50x) and which have uniform (111) texture. This abnormal grain growth is believed to be driven, in part, by surface energy minimization and hence is termed surface-energy-driven secondary grain growth.It was found that n-type dopants, phosphorous and arsenic, markedly enhance the rate of secondary grain growth as seen through a lowering of the temperature required for significant growth. On the other hand, boron (a p-type dopant) appears to neither markedly increase nor decrease the rate of grain growth. Enhancement caused by phosphorous or arsenic is thought to stem from increases in the mobility of the grain boundaries. Enhancement of grain boundary mobility was found to be compensated (reduced or eliminated) by additional doping with boron.
Study of Molybdenum-Alusil Interdiffusion Kinetics and Contact Resistance for VLSI Applications
Authors: Singh R. N. , Brown D. M. , Kim M. J. , Smith G. A. 
Published: March 2011

ABSTRACTInterdiffusion barrier characteristics of molybdenum thin films with Alusil(Al-1% Si) is studied between 733 and 7 63 K via sheet and contact resistance measurements, Rutherford backseattering spectrometry, secondary ion mass spectroscopy, and x-ray diffraction analysis. The results indicate that thermal annealing of Mo/Alusil thin film couples leads to MoAl compound formation initially as a nonplanar front, but extensive annealing results in complete transformation of Alusil to MoAl12 and a significant increase in contact resistance. The interdiffusion kinetics is studied and implications of these observations to VLSI device characteristics is discussed. Based on these results a safe time-temperature processing regime is proposed.
ELECTRICAL RESISTIVITY OF Au-Cr SUPERLATTICES
Authors: BRODSKY M. B. , SOWERS C. H. , SILL L. R. 
Published: March 2011

AbstractSuperlattices of Au-Cr, with Au:Cr=2:l have been prepared. Their electrical resistivities have been measured between 0.3-300 K. Whereas simple ρ-T behavior was found forλ = 30, 51, 90 and 150 Å, complicated behavior, similar to magnetic ordering is found for λ = 45 Å. No correlation is observed with the extremum wavelength for phonon velocities - a maximum occurs at 75 Å - unlike that found for most metallic superlattics.
OPTICAL IMAGING OF DISLOCATIONS IN STRAINED—LAYER SUPERLATTICES AND LATTICE—MISMATCHED EPILAYERS
Authors: GOURLEY P. L. , BIEFELD R. M. , DAWSON L. R. 
Published: March 2011

AbstractWe have developed a convenient photoluminescence microimaging technique to probe misfit dislocations in epitaxially grown semiconductor alloys and multilayers. Using this technique, we have examined the microscopic optical quality of thick (~ 1 μm ) III-V semiconductor epitaxial layers, mismatched to their substrates. The layers includeseveral kinds of [100] strained-layer superlattices (GaP/GaAsxP1-x on GaP and GaAs/GaAs. P on GaAs grown by MOCVD, and GaAs/In Ga1-x As on GaAs grown by MBE) and associated alloys. For each type of superlalti e, we have studied a large number of samples corresponding to different compositions and layer thicknesses. The results show that misfit dislocations can be completely eliminated in the uppermost layers of the strained-layer superlattices if these structures have thin layers, less than the critical thickness for elastic accommodation, and sufficient numbers of interfaces to block threading dislocations.