Stress and texture in sputter deposited Cr films

2003 ◽  
Vol 795 ◽  
Author(s):  
S. Yu. Grachev ◽  
J.-D. Kamminga ◽  
G. C. A. M. Janssen
Keyword(s):  
Tensile Stress ◽  
Film Thickness ◽  
Grain Growth ◽  
Power Law ◽  
Fiber Type ◽  
Intrinsic Stress ◽  
Stress Evolution ◽  
Power Law Exponent ◽  
Sputter Deposited ◽  
Chromium Films

ABSTRACTIntrinsic stress in coatings is often responsible for its performance. We studied tensile stress in sputter deposited chromium films as a function of film thickness and Ar pressure during deposition. We correlate the stress evolution to the grain growth in the polycrystalline films. Both grain growth and stress evolution obey the same power law dependence on thickness. We conclude that the tensile stress is generated at the grain boundaries. The power law exponent did not depend on pressure of Ar and remained 0.36. However, texture and microstructure in the layers changed when pressure was increased from 2×10-2 to 6×10-2 mbar. Texture switched from 110 to 111 fiber type. Grooves and sharp star-like grains were observed at higher pressure. We explain changes in terms of suppressed shadowing and less surface diffusion.

Stress Evolution Kinetics in Ultra Thin Sputtered Au Films

1994 ◽  
Vol 356 ◽  
Author(s):  
Quanmin Su ◽  
Cecile Bailly ◽  
Manfred Wuttig ◽  
Sean Corcoran ◽  
Karl Sieradzki
Keyword(s):  
Surface Morphology ◽  
Scanning Tunnelling Microscopy ◽  
Intrinsic Stress ◽  
Characteristic Relaxation Time ◽  
Stress Evolution ◽  
Sharp Maximum ◽  
Membrane Technique ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy ◽  
Sputter Deposited

AbstractThe stress and microstructure of a thin film evolve in time if the deposition is interrupted or terminated. To establish the parameters which control the kinetics of both processes, ultra thin Au layers were sputter deposited on Si membranes and the stress evolution was monitored by a vibrating membrane technique. The evolution of the surface morphology was studied by scanning tunnelling microscopy. Aging after the termination of each deposition causes stress evolution towards higher tension which, around ambient temperature, follows an exponential law with a characteristic relaxation time of the order of tenths of seconds. This time was found to depend strongly on the accumulated film thickness as well as the surface morphology. The intrinsic stress of the depositing layer increases with the coverage of the film on the substrate. Scanning Tunnelling Microscopy shows that the film grows in a Volmer-Weber mode and that the average stress reaches a sharp maximum as the film become continuous.

Correlation of Polysiloxane Molecular Structure to Shear-Thinning Power-Law Exponent Using Elastohydrodynamic Film Thickness Measurements

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Thomas J. Zolper ◽  
Paul Shiller ◽  
Manfred Jungk ◽  
Tobin J. Marks ◽  
Yip-Wah Chung ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Shear Rate ◽  
Film Thickness ◽  
Power Law ◽  
Shear Thinning ◽  
Macromolecular Structure ◽  
Polymeric Fluid ◽  
Power Law Exponent ◽  
Elastohydrodynamic Film Thickness ◽  
Thickness Measurements

Siloxane-based polymers (polysiloxanes) are susceptible to temporary shear-thinning that manifests as a reduction of elastohydrodynamic film thickness with increasing entrainment speed or effective shear rate. The departure from Newtonian film thickness can be predicted with the power-law exponent ns, an indicator of the severity of shear-thinning in a polymeric fluid that is influenced by the macromolecular structure. In this paper, a combination of extant rheological and tribological models is applied to determine the power-law exponent of several polysiloxanes using film thickness measurements. Film thickness data at several temperatures and slide-to-roll ratios are used to validate the methodology for several siloxane-based polymers with alkyl and aryl branches.

Stress Evolution in Ultra Thin Sputtered Films

1995 ◽  
Vol 405 ◽  
Author(s):  
Quanmin Su ◽  
R. C. Cammarata ◽  
Manfred Wuttig
Keyword(s):  
Surface Morphology ◽  
Scanning Tunneling Microscopy ◽  
Intrinsic Stress ◽  
Scanning Tunneling ◽  
Characteristic Relaxation Time ◽  
Stress Evolution ◽  
Tunneling Microscopy ◽  
Sputtered Films ◽  
Membrane Technique ◽  
Sputter Deposited

AbstractThe stress and microstructure of growing thin films evolve with time if the deposition is interrupted or terminated. To establish the parameters which control both kinetic processes ultra thin Au, Cu and Al layers were sputter deposited on Si membranes and the stress evolution was monitored by a vibrating membrane technique. The related surface morphology was studied by scanning tunneling microscopy. Aging after each deposition causes stress evolution towards higher tension and the evolution of the stress with time follows an exponential law with a characteristic relaxation time of the order of tens of seconds. This time was found to depend strongly on the accumulated film thickness as well as the surface morphology. The intrinsic stress of the growing layer increases with the coverage of the film on substrate. Scanning Tunneling Microscopy (STM) shows that the film grows in a Volmer-Weber (VW) mode and the stress reaches a maximum as the film become continuous.

A Tem Investigation of the Effects of Tensile Stress on Thin Film Microstructure and Surface Morphology

1994 ◽  
Vol 356 ◽  
Author(s):  
Karen E. Harris ◽  
Alexander H. King
Keyword(s):  
Tensile Stress ◽  
Film Thickness ◽  
Grain Growth ◽  
Fiber Texture ◽  
Free Standing ◽  
Transmission Electron ◽  
Nominal Thickness ◽  
Columnar Grains ◽  
Crack Tips ◽  
Film Microstructure

AbstractWe have studied the microscopic effects of tensile stress on film thickness and grain growth in gold thin films of 25nm nominal thickness using transmission electron microscopy. Free-standing films were annealed at 150°C resulting in films with columnar grains and 〈111〉 fiber texture. After repeated anneals, tensile stresses caused by grain growth became large enough to cause cracks to form and propagate diffusively. While tensile stress must eventually result in an overall decrease in film thickness, local specimen thickening in front of crack tips is observed. The tensile stress also profoundly affected grain growth in these films. Grains near crack tips are larger than grains 400nm away from the tips, and elongated grains with axial ratios greater than 15 have been observed in cracked regions of the films.

Regional variation of recession flow power-law exponent

2018 ◽  
Vol 32 (7) ◽  
pp. 866-872 ◽  
Author(s):  
Swagat Patnaik ◽  
Basudev Biswal ◽  
Dasika Nagesh Kumar ◽  
Bellie Sivakumar
Keyword(s):  
Power Law ◽  
Regional Variation ◽  
Power Law Exponent ◽  
Flow Power

Residual Stress Measurement in Silicon Substrate After Local Thermal Oxidation Using Microscopic Raman Spectroscopy

1991 ◽  
Vol 226 ◽  
Author(s):  
Hideo Miura ◽  
Hiroshi Sakata ◽  
Shinji Sakata Merl
Keyword(s):  
Residual Stress ◽  
Raman Spectroscopy ◽  
Tensile Stress ◽  
Oxide Film ◽  
Film Thickness ◽  
Silicon Dioxide ◽  
Thermal Oxidation ◽  
Silicon Substrate ◽  
Nitride Film ◽  
Oxide Film Thickness

AbstractThe residual stress in silicon substrates after local thermal oxidation is discussed experimentally using microscopic Raman spectroscopy. The stress distribution in the silicon substrate is determined by three main factors: volume expansion of newly grown silicon–dioxide, deflection of the silicon–nitride film used as an oxidation barrier, and mismatch in thermal expansion coefficients between silicon and silicon dioxide.Tensile stress increases with the increase of oxide film thickness near the surface of the silicon substrate under the oxide film without nitride film on it. The tensile stress is sometimes more than 100 MPa. On the other hand, a complicated stress change is observed near the surface of the silicon substrate under the nitride film. The tensile stress increases initially, as it does in the area without nitride film on it. However, it decreases with the increase of oxide film thickness, then the compressive stress increases in the area up to 170 MPa. This stress change is explained by considering the drastic structural change of the oxide film under the nitride film edge during oxidation.

scholarly journals Growth Rate Exponents of Richtmyer-Meshkov Mixing Layers

2005 ◽  
Vol 73 (3) ◽  
pp. 461-468 ◽  
Author(s):  
Timothy T. Clark ◽  
Ye Zhou
Keyword(s):  
Flow Field ◽  
Power Law ◽  
Mixing Layer ◽  
Power Laws ◽  
Mixing Layers ◽  
Spatial Gradients ◽  
Power Law Exponent ◽  
Virtual Time ◽  
Time Origin ◽  
Density Ratios

The Richtmyer-Meshkov mixing layer is initiated by the passing of a shock over an interface between fluid of differing densities. The energy deposited during the shock passage undergoes a relaxation process during which the fluctuational energy in the flow field decays and the spatial gradients of the flow field decrease in time. This late stage of Richtmyer-Meshkov mixing layers is studied from the viewpoint of self-similarity. Analogies with weakly anisotropic turbulence suggest that both the bubble-side and spike-side widths of the mixing layer should evolve as power-laws in time, with the same power-law exponent and virtual time origin for both sides. The analogy also bounds the power-law exponent between 2∕7 and 1∕2. It is then shown that the assumption of identical power-law exponents for bubbles and spikes yields fits that are in good agreement with experiment at modest density ratios.

scholarly journals Free Convective MHD Flow Past a Vertical Cone with Variable Heat and Mass Flux

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
J. Prakash ◽  
S. Gouse Mohiddin ◽  
S. Vijaya Kumar Varma
Keyword(s):  
Boundary Layer ◽  
Power Law ◽  
Mass Flux ◽  
Numerical Study ◽  
Convection Boundary Layer ◽  
Vertical Cone ◽  
Local Skin ◽  
Surface Mass ◽  
Flow Past ◽  
Power Law Exponent

A numerical study of buoyancy-driven unsteady natural convection boundary layer flow past a vertical cone embedded in a non-Darcian isotropic porous regime with transverse magnetic field applied normal to the surface is considered. The heat and mass flux at the surface of the cone is modeled as a power law according to qwx=xm and qw*(x)=xm, respectively, where x denotes the coordinate along the slant face of the cone. Both Darcian drag and Forchheimer quadratic porous impedance are incorporated into the two-dimensional viscous flow model. The transient boundary layer equations are then nondimensionalized and solved by the Crank-Nicolson implicit difference method. The velocity, temperature, and concentration fields have been studied for the effect of Grashof number, Darcy number, Forchheimer number, Prandtl number, surface heat flux power-law exponent (m), surface mass flux power-law exponent (n), Schmidt number, buoyancy ratio parameter, and semivertical angle of the cone. Present results for selected variables for the purely fluid regime are compared with the published results and are found to be in excellent agreement. The local skin friction, Nusselt number, and Sherwood number are also analyzed graphically. The study finds important applications in geophysical heat transfer, industrial manufacturing processes, and hybrid solar energy systems.

Sign in / Sign up

Export Citation Format

Share Document