Compressive stress relaxation through buckling of a low-k polymer-thin cap layer system

2003 ◽  
Vol 82 (9) ◽  
pp. 1380-1382 ◽  
Author(s):  
F. Iacopi ◽  
S. H. Brongersma ◽  
K. Maex
Keyword(s):  
Stress Relaxation ◽  
Compressive Stress ◽  
Layer System ◽  
Cap Layer ◽  
Low K

How to exploit ion-induced stress relaxation to grow thick c-BN films

2002 ◽  
Vol 74 (3) ◽  
pp. 489-492 ◽  
Author(s):  
P. Ziemann ◽  
H.-G. Boyen ◽  
N. Deyneka ◽  
P. Widmayer ◽  
F. Banhart
Keyword(s):  
Stress Relaxation ◽  
Compressive Stress ◽  
Ion Irradiation ◽  
Cubic Phase ◽  
Medium Energy ◽  
High Quality ◽  
Induced Stress

A recently developed procedure is reviewed allowing thick (>1 mm), high-quality c-BN films (>80 % c-BN) to be grown. It is based on the observation that compressive stress inevitably present in such films can be released by medium-energy (some hundred keV) ion irradiation without destroying the cubic phase.

Effect of Deposition Conditions on Intrinsic Stress, Phase Transformation and Stress Relaxation in Tantalum Thin Films

1991 ◽  
Vol 239 ◽  
Author(s):  
A. Mutscheller ◽  
L. A. Clevenger ◽  
J.M.E. Harper ◽  
C. Cabrai ◽  
K. Barmakt
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Phase Transformation ◽  
Stress Relaxation ◽  
Compressive Stress ◽  
Stress Relief ◽  
Beta Phase ◽  
Alpha Phase ◽  
Intrinsic Stress

AbstractWe demonstrate that the high temperature polymorphic tantalum phase transition from the tetragonal beta phase to the cubic alpha phase causes complete stress relaxation and a large decrease in the resistance of tantalum thin films. 100 nm beta tantalum thin films were deposited onto thermally oxidized <100> silicon wafers by dc magnetron sputtering with argon. In situ stress and resistance at temperature were measured during temperature-ramped annealing in purified He. Upon heating, films that were initially compressively stressed showed increasing compressive stress due to thermo-elastic deformation from 25 to 550°C, slight stress relief due to plastic deformation from 550 to 700°C and complete stress relief due to the beta to alpha phase transformation at approximately 700–800°C. Incomplete compressive stress relaxation was observed at high temperatures if the film was initially deposited in the alpha phase or if the beta phase did not completely transform into alpha by 800°C. This incomplete beta to alpha phase transition was most commonly observed on samples that had radio frequency substrate bias greater than -100 V. We conclude that the main stress relief mechanism for tantalum thin films is the beta to alpha phase transformation that occurs at 700 to 800°C.

Thermomechanical Mechanism for Delamination of Polymer Coatings From Optical Fibers

1997 ◽  
Vol 119 (2) ◽  
pp. 133-137 ◽  
Author(s):  
W. W. King ◽  
C. J. Aloisio
Keyword(s):  
Compressive Stress ◽  
Optical Fibers ◽  
Single Layer ◽  
Fiber Surface ◽  
Polymer Coatings ◽  
Layer System ◽  
External Disturbances ◽  
Hydrostatic Tension ◽  
Low Modulus ◽  
Radial Tension

Sometimes the polymer coating on an optical fiber is observed to have separated from the fiber over a small portion of the interface. Irregularities on the capstans and sheaves of draw, rewind, coloring, and cabling machines can initiate such delaminations. Subsequent growth would not be anticipated under the condition of radial compressive stress that might be expected for a coating shrinking over a relatively rigid fiber as the composite cools during manufacture. Compressive stress is indeed found at the interface when a single-layer coating is used. However, for a two-layer system, having a high-modulus secondary over a low-modulus primary (for improved protection against microbending), the different rates of thermal expansion can lead to radial tension at the silica/primary interface, and this tension can “drive” the growth of delaminations. A principal result of this study is that the analysis predicts the primary coating, although rubbery, to be approximately in a state of uniform hydrostatic tension. This tensile stress is of substantial magnitude because of constraints imposed by the relatively stiff secondary coating and by the fiber. The existence of significant radial tension at the fiber surface is consistent with experimental observations of induced delaminations, which are seen to grow long after cessation of external disturbances.

Compressive stress-relaxation behavior of bovine growth plate may be described by the nonlinear biphasic theory

1994 ◽  
Vol 12 (6) ◽  
pp. 804-813 ◽  
Author(s):  
Boaz Cohen ◽  
Gail S. Chorney ◽  
Donna P. Phillips ◽  
Harold M. Dick ◽  
Van C. Mow
Keyword(s):  
Stress Relaxation ◽  
Compressive Stress ◽  
Growth Plate ◽  
Relaxation Behavior ◽  
Stress Relaxation Behavior
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