The Effect of Deposition Temperature on the Microstructure of Lpcvd Polysilicon Films

1991 ◽  
Vol 239 ◽  
Author(s):  
J. Hangas ◽  
D. R. Liu ◽  
D. G. Oei ◽  
S. L. McCarthy ◽  
C. Peters
Keyword(s):  
Growth Rate ◽  
Grain Size ◽  
Deposition Temperature ◽  
Hexagonal Phase ◽  
Stacking Faults ◽  
Lattice Parameter ◽  
Dislocation Motion ◽  
Narrow Region ◽  
Thin Oxide Film ◽  
Polysilicon Films

ABSTRACTThe microstructure, of unannealed and annealed polysilicon films was studied using TEM and XRD. The LPCVD films were grown at 600°C and 620°C with 320 mTorr of silane, and at 580°C with 220 mTorr of silane. The substrates were [001] Si with a thin oxide film. The stress state of the films changed from compressive at 580°C and 620°C, to tensile in a narrow region around 600°C. The same materials were annealed at 1100°C. The unannealed films vary from partially amorphous at 580°C, where the slowest growth rate was observed, to randomly oriented and equiaxed at 600°C, to columnar and highly oriented at 620°C. The grains in the 620°C material have a high stacking fault and polytype density, and it was proposed that these occurred on growth, and not from dislocation motion. The grain size increased from 40–250run to 100–300 nm in the 600°C samples when annealed at 1100°C, and the density of twins and stacking faults was reduced. The hexagonal phase was observed only in unannealed materials in SAED and as broad “wings” at the base of the llld.c (diamond cubic) peak in XRD. Within the limits of SAED, no change in lattice parameter of the hexagonal phase was observed.

Thin Film Properties of LPCVD TiN Barrier for Silicon Device Technology

1991 ◽  
Vol 250 ◽  
Author(s):  
Rama I. Hegde ◽  
Robert W. Fiordalice ◽  
Edward O. Travis ◽  
Philip J. Tobin
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Deposition Temperature ◽  
Lattice Parameter ◽  
Microstructural Properties ◽  
Film Properties ◽  
Deposition Rates ◽  
Tin Film ◽  
Silicon Device ◽  
Device Technology

AbstractThin film properties of LPCVD TiN barriers deposited on Si(100), using TiCl4 and NH3 as reactants, were investigated as a function of deposition temperature between 400 °C and 700 °C. The TiN film chemistry and film composition were studied by AES and RBS techniques, while the microstructural properties (grain size, lattice parameter and texture) were evaluated by XRD. The TiN deposition rates and film resistivities were also determined. Finally the film properties of the TiN barriers as determined by surface analysis were related to the process parameters.

The β - 3C to α - 4H transformation in SiC with Al, B, and C additions: Kinetics dominated by growth akin to ostwald ripening

1996 ◽  
Vol 54 ◽  
pp. 658-659
Author(s):  
Warren J. MoberlyChan ◽  
J. J. Cao ◽  
L. C. DeJonghe
Keyword(s):  
Grain Growth ◽  
Ostwald Ripening ◽  
Hexagonal Phase ◽  
Equilibrium Phase ◽  
Stacking Faults ◽  
Beta Phase ◽  
Dislocation Motion ◽  
Alpha Phase ◽  
Large Crystal ◽  
Temperature Equilibrium

The cubic-to-hexagonal phase transformation upon heating SiC has been a focus and/or precondition of hundreds of research studies. In single (or large) crystal SiC, partial dislocation motion propagates stacking faults to invoke the transformation, analogous to the classic FCC-HCP transformation in Co. The hexagonal phase can exist in >200 different stacking modulations of planes of Si-C tetrahedra, with the α-6H polytype regarded as the high temperature equilibrium phase. (“6” is the repeat stacking in a unit cell.) The propensity of stacking faults in all SiC materials provide the nuclei for the transformation. Most transformation studies of polycrystalline SiC cite the work of Heuer, et al., which describes a transformation similar to that in single crystals. The Heuer model incorporates grain growth by observing the nucleated alpha phase as sandwiched between “sheaths” of beta phase, with the sheaths continuing to grow and “protect” the growing alpha phase throughout the transformation. Grain growth incurred during processing is typically treated as kinetically independent of the transformation.

Supercritical Fluid Deposition of Ruthenium Thin Films: A Kinetic Study

2007 ◽  
Vol 992 ◽  
Author(s):  
Christos F. Karanikas ◽  
James J. Watkins
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Deposition Temperature ◽  
Zero Order ◽  
Measurable Effect ◽  
Deposition Rates ◽  
Reaction Pressure ◽  
Deposition Kinetics ◽  
First Order ◽  
Kinetics Of

AbstractThe kinetics of the deposition of ruthenium thin films from the hydrogen assisted reduction of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)(1,5-cyclooctadiene)ruthenium(II), [Ru(tmhd)2cod], in supercritical carbon dioxide was studied in order to develop a rate expression for the growth rate as well as to determine a mechanism for the process. The deposition temperature was varied from 240°C to 280°C and the apparent activation energy was 45.3 kJ/mol. Deposition rates up to 30 nm/min were attained. The deposition rate dependence on precursor concentrations between 0 and 0.2 wt. % was studied at 260°C with excess hydrogen and revealed first order deposition kinetics with respect to precursor at concentrations lower then 0.06 wt. % and zero order dependence at concentrations above 0.06 wt. %. The effect of reaction pressure on the growth rate was studied at a constant reaction temperature of 260°C and pressures between 159 bar to 200 bar and found to have no measurable effect on the growth rate.

Scanning Scratch Tests for Evaluating the Adhesion of Thin Oxide Films on Stainless Steel

1994 ◽  
Vol 356 ◽  
Author(s):  
V. A. C. Haanappel ◽  
H. D. van Corbach ◽  
T. Fransen ◽  
P. J. Gellings
Keyword(s):  
Mechanical Properties ◽  
Growth Rate ◽  
Stainless Steel ◽  
Film Thickness ◽  
Critical Load ◽  
Deposition Temperature ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
Thin Oxide Films ◽  
Type Aisi

AbstractAmorphous alumina films were deposited by metal-organic chemical vapour deposition (MOCVD) on stainless steel, type AISI 304. The MOCVD experiments were performed in nitrogen at low pressure (0.17 kPa (1.25 torr)).The effect of deposition temperature (200 − 380 °C), growth rate, film thickness, and post-deposition thermal treatment on the mechanical properties was studied. The experiments were performed with a scanning-scratch tester. The experiments are based on the estimation of the film adhesion to the substrate by determining a critical load, Lc: the load where the film starts to spall or to delaminate.The best mechanical properties were obtained with unannealed samples. After thermal annealing the critical load decreases. Regarding the unannealed samples, the critical load increased with increasing film thickness. The deposition temperature and the growth rate had no effect on the critical load.

The Effect of Temperature and Pressure on Residual Stress in LPCVD Polysilicon Films

1992 ◽  
Vol 276 ◽  
Author(s):  
D-G. Oei ◽  
S. L. McCarthy
Keyword(s):  
Residual Stress ◽  
Deposition Temperature ◽  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
Effect Of Temperature ◽  
Pressure Chemical ◽  
Polysilicon Films ◽  
Oriented Polycrystalline ◽  
Temperature And Pressure ◽  
Reduced Pressures

ABSTRACTMeasurements of the residual stress in polysilicon films made by Low Pressure Chemical Vapor Deposition (LPCVD) at different deposition pressures and temperatures are reported. The stress behavior of phosphorus (P)-ion implanted/annealed polysilicon films is also reported. Within the temperature range of deposition, 580 °C to 650 °C, the stress vs deposition temperature plot exhibits a transition region in which the stress of the film changes from highly compressive to highly tensile and back to highly compressive as the deposition temperature increases. This behavior was observed in films that were made by the LPCVD process at reduced pressures of 210 and 320 mTORR. At deposition temperatures below 590 °C the deposit is predominantly amorphous, and the film is highly compressive; at temperatures above 610 °C (110) oriented polycrystalline silicon is formed exhibiting high compressive residual stress.

THE EFFECT OF PREPARED PARAMETERS ON THE MICROSTRUCTURE OF ELECTRODEPOSITED NANOCRYSTALLINE NICKEL COATING

2004 ◽  
Vol 11 (04n05) ◽  
pp. 433-442 ◽  
Author(s):  
C. Y. DAI ◽  
Y. PAN ◽  
S. JIANG ◽  
Y. C. ZHOU
Keyword(s):  
Grain Size ◽  
Surface Morphology ◽  
Current Density ◽  
Crystal Orientation ◽  
Nickel Coating ◽  
Pulse Frequency ◽  
Lattice Parameter ◽  
Nanocrystalline Nickel ◽  
Peak Current Density ◽  
Peak Current

The nanocrystalline nickel coating was synthesized by pulse-jet electrodeposition from modified Watts bath. Pulse and jet plating was employed to increase the deposition current density, decrease diffusion layer, increase the nucleation rate and in this case the prepared method would result in fine-grained deposits. Transmission and scanning electron microscopy and X-ray diffraction (XRD) were used to study the microstructure, the surface morphology, the crystal preferred orientation and the variety of the lattice parameter respectively. The influence of pulse parameters, namely peak current density, the duty cycle and pulse frequency on the grain size, surface morphology, crystal orientation and microstructure was studied. The results showed that with increasing peak current density, the deposit grain size was found to decrease markedly in other parameters at constant. However, in our experiment it was found that the grain size increased slightly with increasing pulse frequency. For higher peak current density, the surface morphology was smoother. The crystal orientation progressively changed from an almost random distribution to a strong (111) texture. This means that the peak current density was the dominated parameter to effect the microstructure of electrodeposited nanocrystalline nickel coating. In addition, the lattice parameter for the deposited nickel is calculated from XRD and it is found that the calculated value is less than the lattice parameter for the perfect nickel single crystal. This phenomenon is explained by the crystal lattice mismatch.

Consolidation and properties of Gd0.1Ce0.9O1.95 nanoparticles for solid-oxide fuel cell electrolytes

2006 ◽  
Vol 21 (1) ◽  
pp. 119-124 ◽  
Author(s):  
A.I.Y. Tok ◽  
L.H. Luo ◽  
F.Y.C. Boey ◽  
J.L. Woodhead
Keyword(s):  
Grain Size ◽  
Ionic Conductivity ◽  
Sintering Temperature ◽  
Spherical Shape ◽  
Impedance Analysis ◽  
Lattice Parameter ◽  
Narrow Particle Size Distribution ◽  
Precipitation Process ◽  
Boundary Area ◽  
Co Precipitation

Gd-doped ceria solid solutions have been recognized to be leading electrolytes for use in intermediate-temperature fuel cells. In this paper, the preparation, solubility, and densification of Gd0.1Ce0.9O1.95 ceramics derived from carbonate co-precipitation are reported. The dissolution of Gd2O3 in CeO2 lattice was identified to be completed during the co-precipitation process by studying the lattice parameter as a function of temperature. After calcination at 800 °C for 2 h, the nano-sized Gd0.1Ce0.9O1.95 powder (∼33 nm) with a nearly spherical shape and a narrow particle-size distribution was obtained. This calcined powder has high sinterability and maximum densification rate at ∼1000 °C. Sintering at 1300 °C for 4 h yielded over 97% relative density with near maximum. The grain size increased with increases in sintering temperature. The ionic conductivity of these pellets was tested by alternating current impedance spectroscopy to elucidate the contribution of intragranular and intergranular conductivity to the total ionic conductivity. It was found that sintering temperature does not affect intragranular conductivity, though intergranular conductivity was strongly influenced by grain size, grain boundary area, and relativity density. This pellet sintered at 1500 °C for 4 h showed a high ionic conductivity of 5.90 × 10−2 s/cm when measured at 750 °C. The characterization and structural evaluation of the as-received powders were carried out using x-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller, and dilatometer and impedance analysis.

On the Structure and Some Properties of LaCo Co-substituted NiZn Ferrites Prepared Using the Standard Ceramic Technique

2016 ◽  
Vol 35 (4) ◽  
pp. 417-423 ◽  
Author(s):  
Xiaofei Niu ◽  
Xiansong Liu ◽  
Xin Huang ◽  
Kai Huang ◽  
Yuqi Ma ◽  
...  
Keyword(s):  
Grain Size ◽  
Power Loss ◽  
Low Frequency ◽  
Secondary Phase ◽  
Lattice Parameter ◽  
Initial Permeability ◽  
High Resistivity ◽  
X Ray Diffraction ◽  
Ferrite Sample ◽  
Higher Power

AbstractZn0.5Ni0.5-xCoxFe2-yLayO4 ferrites (with x=0, 0.02 and y=0, 0.02) were prepared by an industrial method using the standard ceramic technique and sintered at 1,250°C in air. X-ray diffraction (XRD) was used to obtain the phase formation of the NiZn ferrites. The microstructure of ferrites was investigated by scanning electron microscopy (SEM). The XRD reveals that lattice parameter (a) is decreased and a secondary phase (LaFeO3) is formed in the La–Co co-substituted NiZn ferrite sample, meanwhile, the grain size (D) of this sample decreased obviously by observing SEM photographs. Vibrating sample magnetometry (VSM), B-H analyzer, impedance analyzer and electrometer were carried out in order to characterize some properties of the ferrites. This investigation indicates that, La–Co co-substituted NiZn ferrite sample has higher power loss (Pcv) than other samples at low frequency with an increase in coercive field (Hc) and magnetocrystalline anisotropy (K1), a decrease in initial permeability (μi) and saturation magnetization (Ms). However, at high frequency, the power loss of La–Co co-substituted sample is low, which is attributed to high resistivity (ρ), small grain size (D), less number of Fe2+ ions and low porosity (P).

Properties and Application of Undoped Hydrogenated Microcrystalline Silicon Thin Films

1989 ◽  
Vol 149 ◽  
Author(s):  
J. Kanicki ◽  
E. Hasan ◽  
D. F. Kotecki ◽  
T. Takamori ◽  
J. H. Griffith
Keyword(s):  
Grain Size ◽  
Deposition Temperature ◽  
Etch Rate ◽  
Chemical Vapor ◽  
Microcrystalline Silicon ◽  
Silicon Thin Films ◽  
Hydrogen Dilution ◽  
Average Grain Size ◽  
Structural And Electrical Properties ◽  
Deposition Conditions

ABSTRACTDevice quality undoped hydrogenated microcrystalline silicon has been prepared by plasma enhanced chemical vapor deposition under different conditions. The dependence of physical, chemical, structural, and electrical properties on the deposition conditions has been investigated. Conductive (conductivity above 10−3Ω−1 cm−1) and resistive (conductivity around 10−9Ω−1cm−1) layers having approximately the same grain size, at a given substrate temperature, have been deposited between 200 and 500°C at two different hydrogen dilutions. Independently of the hydrogen dilution, the average grain sized is dependent on the deposition temperature and the film thickness; and a maximum average grain size of about 40 nm has been achieved for a thick film deposited at 500°C. The density of paramagnetic defects also increases with increasing deposition temperature, which indicates that more dangling bond defects are introduced as the total area of the grain boundaries increases. The etch rate decreases with increasing deposition temperature, and for the films deposited at 250 and 500°C the etch rate has been measured to be 6.6 and 2.7 nm/min, respectively. Thin film transistors incorporating a microcrystalline channel have been fabricated and evaluated. The best device had the following properties: field effect mobility, threshold voltage, and on/off current ratio of about 0.8 cm2/V sec, below 5 V, and around 106, respectively.

scholarly journals Molecular Dynamics Simulation on Creep Behavior of Nanocrystalline TiAl Alloy

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1693
Author(s):  
Fei Zhao ◽  
Jie Zhang ◽  
Chenwei He ◽  
Yong Zhang ◽  
Xiaolei Gao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Grain Size ◽  
Steady State ◽  
High Temperature ◽  
Grain Boundary ◽  
Tial Alloy ◽  
Boundary Diffusion ◽  
Dislocation Motion ◽  
High Temperature Creep ◽  
Creep Stage

TiAl alloy represents a new class of light and heat-resistant materials. In this study, the effect of temperature, pressure, and grain size on the high-temperature creep properties of nanocrystalline TiAl alloy have been studied through the molecular dynamics method. Based on this, the deformation mechanism of the different creep stages, including crystal structure, dislocation, and diffusion, has been explored. It is observed that the high-temperature creep performance of nanocrystalline TiAl alloy is significantly affected by temperature and stress. The higher is the temperature and stress, the greater the TiAl alloy’s steady-state creep rate and the faster the rapid creep stage. Smaller grain size accelerates the creep process due to the large volume fraction of the grain boundary. In the steady-state deformation stage, two kinds of creep mechanisms are manly noted, i.e., dislocation motion and grain boundary diffusion. At the same temperature, the creep mechanism is dominated by the dislocation motion in a high-stress field, and the creep mechanism is dominated by the diffusion creep in the low-stress field. However, it is observed to be mainly controlled by the grain boundary diffusion and lattice diffusion in the rapid creep stage.

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