Thin film scratch testing in two dimensions—Experiments and analysis

1998 ◽  
Vol 13 (4) ◽  
pp. 1002-1014 ◽  
Author(s):  
Maarten P. de Boer ◽  
John C. Nelson ◽  
William W. Gerberich
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Plane Strain ◽  
Interfacial Crack ◽  
Strain Energy Release ◽  
Two Dimensions ◽  
Displacement Curve ◽  
Narrow Strip ◽  
Interfacial Cracks

We have modified the microscratch test to create a near plane strain loading condition. In the Microwedge Scratch Test (MWST), a wedge-shaped diamond indenter tip is drawn along a fine line (i.e., narrow strip of film), while simultaneously being driven into the line. We compare microwedge scratching of zone 1 (voided grain boundaries) and zone T (metallurgical grain boundaries) thin film specimens of sputtered tungsten on thermally grown SiO2. Symptomatic of its weak grain boundaries, the zone 1 film displays three separate crack systems. Because of its superior grain boundary strength, the zone T film displayed only one of these—an interfacial crack system. By correlating fracture phenomena to signature events in the load-displacement curve, we develop governing equations for propagating interfacial cracks, including expressions for strain energy release rate, bending strain, and mode mixity. Grain boundary fracture causes zone 1 films to spall before a stable crack is formed. Zone T films survive the bending strains, and hence adhesions may be inferred from stable crack growth mechanics. We conclude by contrasting and comparing experimental results for plane strain indentation versus plane strain scratching.

scholarly journals Mechanics Of Interfacial Crack Propagation In Microscratching

1996 ◽  
Vol 436 ◽  
Author(s):  
Maarten P. de Boer ◽  
John C. Nelson ◽  
William W. Gerberich
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Grain Boundary ◽  
Interfacial Crack ◽  
Strain Energy Release ◽  
Linear Elastic ◽  
Interfacial Cracks ◽  
Bending Strain ◽  
Diamond Indenter ◽  
Boundary Fracture

AbstractA new probing technique has been developed to test thin film mechanical properties. In the Microwedge Scratch Test (MWST), a wedge shaped diamond indenter tip is drawn along a fine line, while simultaneously being driven into the line. We compare microwedge scratching of Zone 1 and Zone T thin film specimens of sputtered W on SiO2. Symptomatic of its poor mechanical properties, the Zone 1 film displays three separate crack systems. Because of its superior grain boundary strength, the Zone T film displayed only one of these - an interfacial crack system. Using bimaterial linear elastic fracture mechanics, governing equations are developed for propagating interfacial cracks, including expressions for strain energy release rate, bending strain, and mode mixity. Grain boundary fracture strength information may be deduced from the Zone 1 films, while adhesion may be inferred from the Zone T films.

Location Control of Laterally Columnar Si Grains by Dual-Beam Excimer-Laser Melting of Si Thin-Film

2000 ◽  
Vol 621 ◽  
Author(s):  
Ryoichi Ishihara
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Heat Source ◽  
Grain Boundaries ◽  
Excimer Laser ◽  
Laser Melting ◽  
Dual Beam ◽  
Single Grain ◽  
Free Area ◽  
Si Thin Film

ABSTRACTThe offset of the underlying TiW is introduced in the island of Si, SiO2 and TiW on glass. During the dual-beam excimer-irradiation to the Si and the TiW, the offset in TiW acts as an extra heat source, which melts completely the Si film near the edge, whereas the Si inside is partially melted. The laterally columnar Si grains with a length of 3.2 μm were grown from the inside of the island towards the edge. By changing the shape of the edge, the direction of the solidification of the grain was successfully controlled in such a way that the all grain-boundaries are directed towards the edge and a single grain expands. The grain-boundary-free area as large as 4 μm × 3 μm was obtained at a predetermined position of glass.

Degradation of the Strength of a Grain and a Grain Boundary due to the Accumulation of the Structural Defects of Crystal

2018 ◽  
Author(s):  
Guoxiong Zheng ◽  
Yifan Luo ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Tensile Test ◽  
Grain Boundaries ◽  
Intergranular Fracture ◽  
Semiconductor Devices ◽  
Ebsd Analysis ◽  
Structural Defects ◽  
Polycrystalline Materials ◽  
Transgranular Fracture

Various brittle fractures have been found to occur at grain boundaries in polycrystalline materials. In thin film interconnections used for semiconductor devices, open failures caused by electro- and strain-induced migrations have been found to be dominated by porous random grain boundaries that consist of a lot of defects. Therefore, it is very important to explicate the dominant factors of the strength of a grain boundary in polycrystalline materials for assuring the safe and reliable operation of various products. In this study, both electron back-scatter diffraction (EBSD) analysis and a micro tensile test in a scanning electron microscope was applied to copper thin film which is used for interconnection of semiconductor devices in order to clarify the relationship between the strength and the crystallinity of a grain and a grain boundary quantitatively. Image quality (IQ) value obtained from the EBSD analysis, which indicates the average sharpness of the diffraction pattern (Kikuchi pattern) was applied to the crystallinity analysis. This IQ value indicates the total density of defects such as vacancies, dislocations, impurities, and local strain, in other words, the order of atom arrangement in the observed area in nano-scale. In the micro tensile test system, stress-strain curves of a single crystal specimen and a bicrystal specimen was measured quantitatively. Both transgranular and intergranular fracture modes were observed in the tested specimens with different IQ values. Based to the results of these experiments, it was found that there is the critical IQ value at which the fracture mode of the bicrystal specimen changes from brittle intergranular fracture at a grain boundary to ductile transgranular fracture in a grain. The strength of a grain boundary increases monotonically with IQ value because of the increase in the total number of rigid atomic bonding. On the other hand, the strength of a grain decreases monotonically with the increase of IQ value because the increase in the order of atom arrangement accelerates the movement of dislocations. Finally, it was clarified that the strength of a grain boundary and a grain changes drastically as a strong function of their crystallinity.

Competitive Motions of Grain-Boundary and Free Surface in Selecting Thin Film Morphology

1996 ◽  
Vol 441 ◽  
Author(s):  
B. Sun ◽  
Z. Suo ◽  
W. Yang
Keyword(s):  
Thin Film ◽  
Free Energy ◽  
Free Surface ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Analytic Solutions ◽  
Film Morphology ◽  
Polycrystalline Thin Film ◽  
Continuous Film

AbstractDuring annealing of a polycrystalline thin film, grain-boundaries and film surfaces move. If the grain-boundaries move faster, the grains having the lowest free energy grow at the expense of others, resulting in a continuous film with large grains. If the film surfaces move faster, they groove along their junctions with the grain-boundaries, breaking the film to islands. This paper describes analytic solutions for steady surface motions, and discusses the morphology selection.

Grain boundary Diffusion of Ni through Pd2Si

1983 ◽  
Vol 25 ◽  
Author(s):  
E. C. Zingu ◽  
J. W. Mayer
Keyword(s):  
Thin Film ◽  
Activation Energy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Diffusion ◽  
Rutherford Backscattering Spectrometry ◽  
High Mobility ◽  
Grain Boundary Diffusion ◽  
Rutherford Backscattering

ABSTRACTInterdiffusion in the Si<100>/Pd2Si/Ni and Si<111>/Pd2Si/Ni thin film systems has been investigated using Rutherford backscattering spectrometry. Nickel is found to diffuse along the grain boundaries of polycrystalline Pd2Si upon which it accumulates at the Si<100>Pd2Si interface. The high mobility of Ni compared to that of si suggests that Pd diffuses faster than Si along the Pd2Si grain boundaries. An activation energy of 1.2 eV is determined for Ni grain boundary diffusion in Pd2Si.

Exafs Studies of Grain Boundary Diffusion and Segregation

1986 ◽  
Vol 77 ◽  
Author(s):  
S. M. Heald ◽  
H. Chen ◽  
J. M. Tranquada
Keyword(s):  
Thin Film ◽  
Solid State ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Diffusion ◽  
Structural Information ◽  
Solid State Diffusion ◽  
Interface Reactions ◽  
Tin Bronze ◽  
State Diffusion

ABSTRACTThe dominant pathway for thin film interdiffusion and interface reactions is often via grain boundaries. We have made EXAFS measurements of grain boundary constituents for two systems: interdiffusion in Ag-Au bilay-ers and solid state reaction of Nb with a copper-tin bronze to form Nb3Sn. The Ag-Au results indicate that Au in saturated Ag grain boundaries has an environment similar to a dilute Au in Ag solution with reduced coordination. For the Nb-bronze reaction, the results for the Cu environment indicate distinct changes in the grain boundary environment when small amounts of Ti, Hf, Zr, and Ta are added to the starting Nb. Both results demonstrate the ability of EXAFS to probe grain boundary environments, and to provide important structural information in understanding solid state diffusion and interdiffusion in thin film systems.

scholarly journals Effect of Grain Boundary Structure on Grain Boundary Diffusivities in the Au/Ag System

1990 ◽  
Vol 209 ◽  
Author(s):  
Qing Ma ◽  
R. W. Balluffi
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Tilt Angle ◽  
Structural Unit ◽  
Boundary Structure ◽  
Grain Boundary Structure ◽  
Unit Model ◽  
Tilt Boundaries ◽  
Accumulation Method

ABSTRACTGrain boundary chemical diffusivities for a series of symmetric [001] tilt boundaries in the Au/Ag system were measured by the surface accumulation method using newly developed thin-film multi-crystal specimens, in which the grain boundaries feeding the accumulation surface were all of the same type. Possible effects due to segregation at the grain boundaries and surfaces were avoided. CSL boundaries of low-Σ ( i.e., 5, 13, 17, 25) and also more general boundaries with tilt angles between the low-Σ orientations were selected. The diffusivities were found to vary monotonically with tilt angle ( i.e., no cusps at low-Σ's were found) in a manner consistent with the Structural Unit model.

(110) facets and dislocation structure of low-angle grain boundaries in YBa2Cu3O7−δ and Y0.7Ca0.3Ba2Cu3O7−δ thin film bicrystals

2007 ◽  
Vol 22 (4) ◽  
pp. 950-957 ◽  
Author(s):  
Xueyan Song
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Dislocation Structure ◽  
Current Flow ◽  
Dislocation Core ◽  
Current Transport ◽  
Contrast Imaging ◽  
Grain Boundary Plane ◽  
Z Contrast

The facet and dislocation structure of 5° and 7° [001]-tilt grain boundaries of YBa2Cu3O7−δ (YBCO) and Y0.7Ca0.3Ba2Cu3O7−δ (YCaBCO) thin film bicrystals were studied. A 24° [001]-tilt YBCO grain boundary was also examined to contrast with the low angle grain boundary faceting behavior. All the low-angle grain boundaries exhibit strong faceting along (100)/(010) and (110) and possess both straight symmetric segments containing equally spaced [100] unit dislocations and step asymmetric segments composed of (110) and (100)/(010) facets. Grain boundaries with a higher degree of meander acquired up to 40% (110) facets. The atomic structure of (110) facets was revealed by the atomic resolution Z-contrast imaging. The (110) facets are dissociated for both the YBCO and YCaBCO grain boundaries. We also found the Ca-doped (110) facets to be more extended along the grain boundary plane, consistent with our earlier finding of a dissociated dislocation core in Ca-doped (100) facets. These 5° and 7° misorientations that we studied are just in the range at which YBCO grain boundaries start to become obstacles to current flow. The above results will be helpful for understanding the current transport across YBCO low-angle grain boundaries.

Nanoindentation study of slip transfer phenomenon at grain boundaries

2009 ◽  
Vol 24 (3) ◽  
pp. 607-615 ◽  
Author(s):  
T.B. Britton ◽  
D. Randman ◽  
A.J. Wilkinson
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Cold Work ◽  
Pure Copper ◽  
Displacement Curve ◽  
Interstitial Free ◽  
Face Centered Cubic ◽  
Slip Transfer ◽  
Individual Contributions ◽  
Face Centered

Nanoindentation was undertaken near grain boundaries to increase understanding of their individual contributions to the material’s macroscopic mechanical properties. Prior work with nanoindentation in body-centered cubic (bcc) materials has shown that some grain boundaries produce a “pop-in” event, an excursion in the load–displacement curve. In the current work, grain boundary associated pop-in events were observed in a Fe–0.01 wt% C polycrystal (bcc), and this is characteristic of high resistance to intergranular slip transfer. Grain boundaries with greater misalignment of slip systems tended to exhibit greater resistance to slip transfer. Grain boundary associated pop-ins were not observed in pure copper (face-centered cubic) or interstitial free steel ~0.002 wt% C (bcc). Additionally, it was found that cold work of the Fe–0.01 wt% C polycrystal immediately prior to indentation completely suppressed grain boundary associated pop-in events. It is concluded that the grain boundary associated pop-in events are directly linked to interstitials pinning dislocations on or near the boundary. This links well with macroscopic Hall–Petch effect observations.

Impedance Spectroscopy Analysis of p Type Li Doped ZnO Thin Film Effect

2011 ◽  
Vol 415-417 ◽  
pp. 1925-1932 ◽  
Author(s):  
Kuo Chuang Chiu ◽  
Yu Han Wu
Keyword(s):  
Thin Film ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Complex Impedance ◽  
Spectroscopy Analysis ◽  
Boundary Conductivity ◽  
Impedance Spectroscopy Technique ◽  
P Type ◽  
Li Content

Impedance spectroscopy technique was employed to characterize the LixZn1-xO2 (x=0.001~0.008) polycrystalline thin film. IS is shown to be an efficient method capable of detecting the contributions of the resistances of grains and grain boundaries resistance to the complex impedance of a compound, accurately estimating its electrical conductivity as well as its corresponding activation energies and conclude on its structural properties. This is demonstrated for the case of lithium segregation in the grain/grain boundary of LixZn1-xO2., we found that the activation energy decrease associated with grain-boundary conductivity reflects the onset of the segregation of excessive Li in the grain boundaries when the Li-content exceeds 0.5 mol%. For Li-content below 0.5mol% is the detection of a transition from p-type conductivity. It might be due to that the Li+ doped mainly in grains and no precipitation observed on the grain boundaries. So we could be process stable p type thin film for Li content below 0.5mol%.

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