Energy Storage And Recovery In Thin Metal Films On Substrates

1997 ◽  
Vol 505 ◽  
Author(s):  
Shefford P Baker ◽  
Rose-Marie Keller ◽  
Eduard Arzt
Keyword(s):  
Plastic Deformation ◽  
Strain Energy ◽  
Dislocation Line ◽  
Line Length ◽  
Metal Films ◽  
Silicon Substrates ◽  
Cu Films ◽  
Compressive Flow ◽  
Film Substrate ◽  
Increasing Temperature

ABSTRACTDislocation segments which extend through the thickness of a film can move through the film only if dislocation line length is deposited or removed at the film/substrate and film/passivation (if any) interfaces. The dislocation density and, therefore, the energy stored in the film increase during plastic deformation. The reverse process, that is, the reduction of strain energy in the film by the reduction of dislocation line length, is here suggested to be the origin of a number of unexplained features of experimentally obtained stress-temperature curves, including very low (or even “negative”) yield stresses in compression, tensile-compressive flow stress asymmetries, increasing strength with increasing temperature upon heating, and a very strong Bauschinger-like effect which has been seen in thin Cu films. The results of stress-temperature measurements of passivated Cu thin films on silicon substrates are presented.

Practical Application of a Geometrically Nonlinear Stress-Curvature Relation

1991 ◽  
Vol 239 ◽  
Author(s):  
Christine B. Masters ◽  
N. J. Salamon
Keyword(s):  
Strain Energy ◽  
Film Stress ◽  
Silicon Substrates ◽  
Substrate Thickness ◽  
Geometrically Nonlinear ◽  
Practical Application ◽  
Total Strain Energy ◽  
Initial Film ◽  
Nonlinear Stress ◽  
Film Substrate

ABSTRACTA recently developed geometrically nonlinear stress-curvature relation based on a minimization of the total strain energy, which predicts a bifurcation in shape as the magnitude of intrinsic film stress increases, is discussed in this paper. It is compared with the linear theories of Stoney and Brenner & Senderoff for a thin molybdenum film on silicon substrates with various thicknesses. Although the ratio of film to substrate elastic modulus is only 2, Stoney's equation generates significant error for this film/substrate system and the Brenner & Senderoff relation should be used for calculating initial film stress when plate deflections are small. When deflections exceed approximately half the substrate thickness the Brenner & Senderoff equation produces over 10% error and consequently, the nonlinear stress-deflection relation should be used to relate plate curvatures to initial film stress.

Barriers to Strain Relaxation in Epitaxial Fluorides on Si(111)

1993 ◽  
Vol 308 ◽  
Author(s):  
Weidan Li ◽  
Steve Hymes ◽  
Shyam P. Murarka ◽  
Leo J. Schowalter
Keyword(s):  
Plastic Deformation ◽  
Temperature Dependence ◽  
Mechanical Stress ◽  
Temperature Change ◽  
Energy Barrier ◽  
Strain Energy ◽  
Strain Relaxation ◽  
Dislocation Motion ◽  
Unusual Behavior ◽  
Increasing Temperature

ABSTRACTThe mechanical stress of epitaxial SrF2 and CaF2 films on Si(111) substrates has been measured as a function of temperature by the substrate curvature technique. The temperature dependence of the stress in the SrF2 film is interpreted in terms of an energy barrier to dislocation motion. When the strain energy is smaller than the value needed to overcome the barrier, the change in stress is due mainly to elastic deformation. As the temperature change increases, the strain energy becomes large enough to overcome the barrier, at which point plastic deformation initiates. Unlike SrF2, the stress behavior of the CaF2 film for increasing temperature is quite different from its behavior for decreasing temperature. This unusual behavior is not understood at this time.

Plasticity in Copper Thin Films

1999 ◽  
Vol 594 ◽  
Author(s):  
V. Weihnacht ◽  
W. Brückner
Keyword(s):  
Thin Films ◽  
Plastic Deformation ◽  
Thermal Cycling ◽  
Thermal Cycle ◽  
Cu Films ◽  
Strain Behavior ◽  
Four Point Bending ◽  
Dislocation Arrangement ◽  
Tension And Compression ◽  
Film Substrate

AbstractPlastic deformation in thin Cu films was studied by stress measurements with the wafercurvature technique during thermal cycling and in combination with four-point bending. The results from 0.5 ¼m and 1 ¼m thick Cu films are compared. In thermal cycling experiments, strengthening during cooling and a Bauschinger-like effect during reheating were observed. The stress-strain behavior investigated by four-point bending showed to be asymmetric regarding tension and compression at lower temperatures. These phenomenons are explained by a dislocation arrangement at the film-substrate interface which has formed during a previous thermal cycle.

Parallel Glide: A Fundamentally Different Type of Dislocation Motion in Ultrathin Metal Films

2003 ◽  
Vol 779 ◽  
Author(s):  
T. John Balk ◽  
Gerhard Dehm ◽  
Eduard Arzt
Keyword(s):  
Thermal Cycling ◽  
Grain Boundaries ◽  
Film Surface ◽  
Metal Films ◽  
Geometric Constraints ◽  
Film Stress ◽  
Diffusional Creep ◽  
Creep Model ◽  
Substrate Interface ◽  
Film Substrate

AbstractWhen confronted by severe geometric constraints, dislocations may respond in unforeseen ways. One example of such unexpected behavior is parallel glide in unpassivated, ultrathin (200 nm and thinner) metal films. This involves the glide of dislocations parallel to and very near the film/substrate interface, following their emission from grain boundaries. In situ transmission electron microscopy reveals that this mechanism dominates the thermomechanical behavior of ultrathin, unpassivated copper films. However, according to Schmid's law, the biaxial film stress that evolves during thermal cycling does not generate a resolved shear stress parallel to the film/substrate interface and therefore should not drive such motion. Instead, it is proposed that the observed dislocations are generated as a result of atomic diffusion into the grain boundaries. This provides experimental support for the constrained diffusional creep model of Gao et al.[1], in which they described the diffusional exchange of atoms between the unpassivated film surface and grain boundaries at high temperatures, a process that can locally relax the film stress near those boundaries. In the grains where it is observed, parallel glide can account for the plastic strain generated within a film during thermal cycling. One feature of this mechanism at the nanoscale is that, as grain size decreases, eventually a single dislocation suffices to mediate plasticity in an entire grain during thermal cycling. Parallel glide is a new example of the interactions between dislocations and the surface/interface, which are likely to increase in importance during the persistent miniaturization of thin film geometries.

scholarly journals How long is a curved beam?

2005 ◽  
Vol 40 (3) ◽  
pp. 295-297 ◽  
Author(s):  
N. G Stephen
Keyword(s):  
Strain Energy ◽  
Line Length ◽  
Curved Beam ◽  
Centre Line

For a straight or thin curved beam, the expression for strain energy due to bending is U = M2 L/(2EI); for this to be applicable to a thick curved beam, the requisite length is slightly greater than the centre-line length.

Effect of Plastic Deformation on the Strain Energy Release Rate in a Centrally Notched Plate Subjected to Uniaxial Tension

1966 ◽  
Vol 88 (1) ◽  
pp. 82-86 ◽  
Author(s):  
R. G. Forman
Keyword(s):  
Plastic Deformation ◽  
Energy Release Rate ◽  
Energy Release ◽  
Uniaxial Tension ◽  
Correction Factor ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Linear Elastic

This paper presents theoretical studies on the effect of plastic deformation on the strain energy release rate, G, of a plate under uniaxial tension with a central propagating crack. The linear elastic fracture mechanics solution for G is improved by using the Dugdale model for the crack and yielded region to obtain the axial rigidity of the plate. The axial rigidity is then used to obtain the solution for the strain energy release rate as the crack propagates. It is found that plastic deformation has a pronounced effect on G. A correction factor is presented for correcting the linear elastic solution for the strain energy release rate. The correction factor is found to depend upon the nominal (gross) stress to material yield stress ratio and the crack length to plate width ratio.

Supercritical fluid immersion deposition: a new process for selective deposition of metal films on silicon substrates

2005 ◽  
Vol 190 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Xiang R. Ye ◽  
Chien M. Wai ◽  
Yuehe Lin ◽  
James S. Young ◽  
Mark H. Engelhard
Keyword(s):  
Supercritical Fluid ◽  
Metal Films ◽  
Silicon Substrates ◽  
Selective Deposition ◽  
New Process

Texture Evolution in Cu Films and Lines

2007 ◽  
Vol 990 ◽  
Author(s):  
Chia-Jeng Chung ◽  
David Field ◽  
No-Jin Park ◽  
Christy Woo
Keyword(s):  
Grain Growth ◽  
Strain Energy ◽  
Texture Evolution ◽  
Growth Conditions ◽  
Geometric Constraints ◽  
In Situ Observation ◽  
Processing Conditions ◽  
Cu Films ◽  
Unique Character

ABSTRACTGrain growth in polycrystalline films is controlled by the energetics of the surface, interface and grain boundaries as well as strain energy. The unique character of damascene lines fabricated from electroplated Cu films introduces the additional considerations of bath chemistry and geometric constraints. The moderate stacking fault energy of Cu allows for the development of a substantial twin fraction for certain growth conditions. This paper discusses in-situ observation of grain growth in Cu films and lines under various processing conditions. It is shown that for thicker films and for structures constrained within damascene trenches the energetics of twin boundary formation play a large role in texture development of these structures.

Sign in / Sign up

Export Citation Format

Share Document