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.

Enhanced Diffusional Self-Healing of Polycrystalline Thin Films

2005 ◽  
Vol 237-240 ◽  
pp. 524-530
Author(s):  
Eugen Rabkin ◽  
Leonid Klinger
Keyword(s):  
Thin Films ◽  
Grain Boundaries ◽  
Initial Distribution ◽  
Self Healing ◽  
Small Surface ◽  
Surface Flattening ◽  
Substrate Interface ◽  
Surface Diffusivity ◽  
Leading Role ◽  
Film Substrate

We considered the flattening of perturbed surface of a thin stress-free polycrystalline film with columnar microstructure deposited on rigid substrate. We show that the mass transport along the film/substrate interface and along the grain boundaries significantly contributes to the overall rate of surface flattening of the film. The diffusion along the film/substrate interface and along the grain boundaries is driven by the capillary stresses in the film. Using the approximation of small surface slopes, we calculated the distribution of capillary stresses in the film, and derived an explicit expression for the temporal behavior of the film topography. The initial distribution of the capillary stresses rapidly relaxes to the steady-state one that does not allow the accumulation of bending strain in the film. For the films with passivated or contaminated surfaces exhibiting reduced surface diffusivity the interfacial and grain boundary diffusion play a leading role in kinetics of surface flattening. The flattening process can be accelerated in this case by several orders of magnitude. The results of our work can be helpful in design of thin films and coatings with enhanced selfhealing capabilities.

Metal Microstructures in Advanced CMOS Devices

1996 ◽  
Vol 54 ◽  
pp. 358-359
Author(s):  
L. M. Gignac ◽  
K. P. Rodbell
Keyword(s):  
Grain Boundaries ◽  
Semiconductor Device ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Metal Films ◽  
Thin Metal ◽  
Electrical Performance ◽  
Thin Metal Films ◽  
Chemical Vapor Deposited ◽  
Boundary Properties

As advanced semiconductor device features shrink, grain boundaries and interfaces become increasingly more important to the properties of thin metal films. With film thicknesses decreasing to the range of 10 nm and the corresponding features also decreasing to sub-micrometer sizes, interface and grain boundary properties become dominant. In this regime the details of the surfaces and grain boundaries dictate the interactions between film layers and the subsequent electrical properties. Therefore it is necessary to accurately characterize these materials on the proper length scale in order to first understand and then to improve the device effectiveness. In this talk we will examine the importance of microstructural characterization of thin metal films used in semiconductor devices and show how microstructure can influence the electrical performance. Specifically, we will review Co and Ti silicides for silicon contact and gate conductor applications, Ti/TiN liner films used for adhesion and diffusion barriers in chemical vapor deposited (CVD) tungsten vertical wiring (vias) and Ti/AlCu/Ti-TiN films used as planar interconnect metal lines.

Preparation and Characterization of Magnetic Force Microscopy Tips Coated with Nickel Films by e-Beam Evaporation

2018 ◽  
Vol 765 ◽  
pp. 3-7
Author(s):  
Badin Damrongsak ◽  
Samutchar Coomkaew ◽  
Karnt Saengkaew ◽  
Ittipon Cheowanish ◽  
Pongsakorn Jantaratana
Keyword(s):  
Film Thickness ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Film Surface ◽  
Electron Beam Evaporation ◽  
Film Stress ◽  
Nickel Films ◽  
Force Microscopy ◽  
Best Response ◽  
Cantilever Bending

In this work, magnetic force microscopy (MFM) tips coated with a nickel thin-film were prepared and characterized for applications in the measurement of the magnetic write field. Nickel films with various thicknesses in a range of 20 – 80 nm were deposited on silicon substrates and silicon atomic force microscopy (AFM) tips by electron beam evaporation. Film surface morphologies and magnetic properties of the coated nickel films were investigated by using AFM and vibrating sample magnetometry (VSM). The rms roughness increased with the film thickness and was in a range between 0.1 and 0.3 nm. VSM results revealed that the mean coercive field of the nickel films was 20 Oe and there was an increase in the coercivity as the film thickness increased. In addition, the prepared MFM tips were evaluated for the tip response to the dc and ac magnetic field generated from perpendicular write heads. It was found that the MFM tip had the best response to the write field when coated with 60 nm thick nickel film. The coating thickness over 60 nm was inapplicable due to the cantilever bending caused by the film stress.

Photo-crystallization in a-Se layer structures: Effects of film-substrate interface-rigidity

2014 ◽  
Vol 116 (19) ◽  
pp. 193511 ◽  
Author(s):  
G. P. Lindberg ◽  
T. O'Loughlin ◽  
N. Gross ◽  
A. Mishchenko ◽  
A. Reznik ◽  
...  
Keyword(s):  
Substrate Interface ◽  
Layer Structures ◽  
Film Substrate

Self-Ordered Vicinal-Surface-Like Nanosteps at the Thin Metal-Film/Substrate Interface

2012 ◽  
Vol 116 (22) ◽  
pp. 12149-12155 ◽  
Author(s):  
Shirly Borukhin ◽  
Cecile Saguy ◽  
Maria Koifman ◽  
Boaz Pokroy
Keyword(s):  
Metal Film ◽  
Thin Metal Film ◽  
Thin Metal ◽  
Vicinal Surface ◽  
Substrate Interface ◽  
Film Substrate

Exotic Doping for Zno Thin Films: Possibility of Monolithic Optical Integrated Circuit

1999 ◽  
Vol 574 ◽  
Author(s):  
Norifumi Fujimura ◽  
Tamaki Shimura ◽  
Toshifumi Wakano ◽  
Atsushi Ashida ◽  
Taichiro Ito
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Nonlinear Optic ◽  
Integrated Circuit ◽  
Film Surface ◽  
Zno Thin Films ◽  
Process Window ◽  
Electro Optic ◽  
Film Substrate ◽  
Optical Integrated Circuit

AbstractWe propose the application of ZnO:X (X = Li, Mg, N, In, Al, Mn, Gd, Yb etc.) films for a monolithic Optical Integrated Circuit (OIC). Since ZnO exhibits excellent piezoelectric effect and has also electro-optic and nonlinear optic effects and the thin films are easily obtained, it has been studied as one of the important thin film wave guide materials especially for an acoustooptic device[1]. In terms of electro-optic and nonlinear optic effects, however, LiNbO3 or LiTaO3 is superior to ZnO. The most important issue of thin film waveguide using such ferroelectrics is optical losses at the film/substrate interface and the film surface, because the process window to control the surface morphology is very narrow due to their high deposition temperature. Since ZnO can be grown at extremely low temperature, the roughness at the surface and the interface is expected to be minimized. This is the absolute requirement especially for waveguide using a blue or ultraviolet laser. Recently, lasing at the wavelength of ultraviolet, ferroelectric and antiferromagnetic behaviors of ZnO doped with various exotic elements (exotic doping) have been reported. This paper discusses the OIC application of ZnO thin films doped with exotic elements.

Nucleation and Heterointerface Structure of InAs Epilayers Grown on InP Substrates

1992 ◽  
Vol 280 ◽  
Author(s):  
K. S. Chandra Sekhar ◽  
A. K. Ballal ◽  
L. Salamanca-Riba ◽  
D. L. Partin
Keyword(s):  
Surface Morphology ◽  
Electronic Properties ◽  
Growth Temperature ◽  
High Speed ◽  
Interface Roughness ◽  
Structural Defects ◽  
Lower Growth ◽  
Substrate Interface ◽  
Film Substrate ◽  
Inp Substrates

ABSTRACTHeteroepitaxial growth of indium arsenide films on indium phosphide substrates is being actively pursued since the electronic properties of these films make them promising materials for optoelectronic and other high speed devices. The various structural aspects of the film that affect their electronic properties are structural defects like dislocations, film-substrate interface roughness and chemical inhomogeneities. In InAs films, electrons accumulate at the film-air interface, making surface morphology an important factor that decides the electronic properties. The InAs films used in this study were grown on InP substrates by metal organic vapor deposition, at different temperatures. A higher growth temperature not only resulted in poor surface morphology of the film, but also created a rough film-substrate interface. However, at all deposition temperatures, the film-substrate interfaces are sharp. At lower growth temperature, the interfaces were flat. Films grown at lower temperatures had good surface morphology and a flat and shaip heterointerface.

On the Role of Surface Diffusion in Stress Relaxation During Electromigration

1995 ◽  
Vol 391 ◽  
Author(s):  
L.M. Klinger ◽  
L. Levin ◽  
E.E. Glickman
Keyword(s):  
Stress Relaxation ◽  
Surface Diffusion ◽  
Hydrostatic Stress ◽  
Stress Gradient ◽  
Film Surface ◽  
Diffusional Creep ◽  
Atomic Diffusion ◽  
Material Transport ◽  
Diffusional Flux

AbstractWe report on the role of surface diffusion involved in relaxation of electromigration (EM) induced compressive stresses in relation to hillock growth and EM behavior of interconnects. Two competing mechanisms of EM stress relaxation by material transport onto the surface are considered. The first is hillocking by threshold diffusional creep (TCH), with rather large blocks of material (grains or group of grains) involved in plastic flow. The second mechanism, atomic diffusion hillocking (ADH), is presumed to be a nonthreshold one, and represents atomic grain boundary (GB) diffusion stimulated by the hydrostatic stress gradient in the direction normal to the film surface. The latter process involves surface diffusion because GB diffusional flux onto the surface must be coupled with the flux of redistribution of the atoms over the surface. If ADH acts rapidly, this should prevent the build-up of the matter at the down-wind (anode) end of the stripe, and thus, eliminate the Blech EM threshold resulting from the stress-gradient along the stripe. The question as to whether GB diffusion capable of transporting atoms pushed by electron wind along the stripe is also effective in relieving compressive stress by GB migration of the surplus atoms in the normal direction, has remained open up to now. The problem is especially acute for short or/and narrow lines separated into short polycrystalline segments, where the Blech threshold effects are critical to EM reliability.We derived the main features of the EM behavior in drift velocity test geometry assuming that both TCH and ADH are operative. The result can be compared with available and future experimental observations in order to reveal if and when the ADH mechanism with surface diffusion involved works.

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