Determining a Lower Bound Mixed Mode Failure Curve for An Interface Crack Between Single Crystal Silicon and Silicone Rubber

2020 ◽  
Vol 88 (2) ◽  
Author(s):  
Subramanyam Reddy Matli ◽  
Ella Rubin ◽  
Leslie Banks-Sills
Keyword(s):  
Lower Bound ◽  
Energy Release ◽  
Interface Crack ◽  
Silicone Rubber ◽  
Mixed Mode ◽  
Single Crystal Silicon ◽  
Brazilian Disk ◽  
Crystal Silicon ◽  
Linear Elastic ◽  
Mode Failure

Abstract An interface crack between single crystal silicon (SC-Si) and silicone rubber is examined. The first term of the asymptotic solution for this interface crack is derived. Mixed mode fracture tests were performed on Brazilian disk specimens at different mode mixities. Finite element analyses (FEAs) of these tests were carried out in abaqus. A cubic (anisotropic) material model is used for SC-Si. Two different material models were used for silicone rubber: a linear elastic model for the asymptotic solution and a Mooney–Rivlin (hyperelastic) model for the FEA. The FEAs showed that large deformations were relegated to a small region surrounding the crack tip. Hence, a K-dominate region exists in which linear elastic fracture mechanics (LEFM) may be used. From the FEAs of the Brazilian disk specimens, energy release rates were determined using the virtual crack closure technique (VCCT) and displacement extrapolation (DE) methods which were corroborated by J-integral values evaluated using the contour integral method. Elsewhere, it was demonstrated that properly implemented, the VCCT method may be used for interface cracks. A mixed mode failure criterion is obtained from the energy release rate data. The SC-Si failed before the interface crack propagated. Hence, the failure curve obtained in this study should be considered as a lower bound of the critical energy release rate for this material pair.

Micro-Scale Cantilever Testing of Linear Elastic and Elastic-Plastic Materials

2012 ◽  
Vol 525-526 ◽  
pp. 57-60 ◽  
Author(s):  
J.E. Darnbrough ◽  
S. Mahalingam ◽  
Peter E.J. Flewitt
Keyword(s):  
Mechanical Properties ◽  
Single Crystal Silicon ◽  
Ion Milling ◽  
Crystal Silicon ◽  
Micro Scale ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Dual Beam ◽  
The Individual ◽  
Elastic Plastic Materials

t is increasingly a requirement to be able to determine the mechanical properties of materials: (i) at the micro-scale, (ii) that are in the form of surface coatings and (iii) that have nanoscale microstructures. As a consequence micro-scale testing is an important tool that has been developed to aid the evaluation of the mechanical properties of such materials. In this work cantilever beam specimens (typically 2μm by 2μm by 10μm in size) have been prepared by gallium ion milling and then deformed in-situ within a FEI Helios Dual Beam workstation. The latter is achieved using a force probe with a geometry suitable for loading the micro-scale test specimens. Thus force and displacement can be measured together with observing the deformation and fracture of the individual specimens. This paper considers the evaluation of the mechanical properties in particular elastic modulus, yield strength and fracture strength of materials that result in relatively large deflections to the micro-scale cantilever beams. Two materials are considered the first is linear elastic single crystal silicon and the other elastic-plastic nanocrystalline (nc) nickel. The results are discussed with respect to the reproducibility of this method of mechanical testing and the evaluated properties are compared with those derived by alternative procedures.

Simulation of near-Crack-Tip Strain Fields on Single-Crystal Silicon Wafer

2012 ◽  
Vol 430-432 ◽  
pp. 404-407
Author(s):  
J.J. Li ◽  
C.W. Zhao ◽  
Y.M. Xing ◽  
Z.Y. Lv ◽  
Y.G. Du
Keyword(s):  
Single Crystal ◽  
Silicon Wafer ◽  
Single Crystal Silicon ◽  
Crack Tip ◽  
Tensile Load ◽  
Crystal Silicon ◽  
Strain Fields ◽  
Single Crystal Silicon Wafer ◽  
Linear Elastic ◽  
Technological Developments

The failure components made of silicon is an important issue in the electronic and nano-technological developments. A study on the near-crack-tip deformation of single-crystal silicon wafer under tensile load was presented. The strain formulas around the crack tip of mode I crack were deduced from linear elastic fracture mechanics. The strain fields around the crack tip were simulated and analyzed in detail.

scholarly journals Brittle Failure of Nanoscale Notched Silicon Cantilevers: A Finite Fracture Mechanics Approach

2020 ◽  
Vol 10 (5) ◽  
pp. 1640 ◽  
Author(s):  
Pasquale Gallo ◽  
Alberto Sapora
Keyword(s):  
Fracture Mechanics ◽  
Brittle Failure ◽  
Process Zone ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Linear Elastic ◽  
Finite Fracture Mechanics ◽  
Generalized Stress Intensity Factors ◽  
Fracture Tests ◽  
Elastic Fracture

The present paper focuses on the Finite Fracture Mechanics (FFM) approach and verifies its applicability at the nanoscale. After the presentation of the analytical frame, the approach is verified against experimental data already published in the literature related to in situ fracture tests of blunt V-notched nano-cantilevers made of single crystal silicon, and loaded under mode I. The results show that the apparent generalized stress intensity factors at failure (i.e., the apparent generalized fracture toughness) predicted by the FFM are in good agreement with those obtained experimentally, with a discrepancy varying between 0 and 5%. All the crack advancements are larger than the fracture process zone and therefore the breakdown of continuum-based linear elastic fracture mechanics is not yet reached. The method reveals to be an efficient and effective tool in assessing the brittle failure of notched components at the nanoscale.

scholarly journals Interface Crack Approaching a Three-Material Joint

2020 ◽  
Vol 10 (1) ◽  
pp. 416 ◽  
Author(s):  
Jelena M. Djoković ◽  
Ružica R. Nikolić ◽  
Robert Ulewicz ◽  
Branislav Hadzima
Keyword(s):  
Plastic Zone ◽  
Energy Release ◽  
Interface Crack ◽  
Crack Deflection ◽  
The Other ◽  
Elastic Behavior ◽  
Release Rates ◽  
Linear Elastic ◽  
Energy Release Rates ◽  
Elastic Fracture

The problem of an interface crack that approaches a three-material joint with two interfaces is analyzed in this paper. Two possible cases are considered: the crack that lies at the interface between materials A and B, approaching the joint of materials A, B, and C, deflects into the interface between materials A and C or into the interface between materials B and C. Analysis is performed within restrictions imposed by the linear elastic fracture mechanics (LEFM), linear elastic behavior of materials, and the small plastic zone around the crack tip, based on the crack deflection criterion proposed by He and Hutchinson. That criterion is applied in this paper to a joint of the three homogeneous isotropic materials. The energy release rates for the crack deflection into one interface or the other are compared to each other, and, based on this comparison, a conclusion is drawn as to which of the two interfaces the crack would deflect. If the value of the ratio of the energy release rates GBC/GAC is greater than the ratio of the corresponding fracture toughnesses of the two interfaces, the crack will deflect into the BC interface. If this ratio is smaller than the ratio of the corresponding fracture toughnesses, the crack will deflect into the AC interface. Knowing the ratio of energy release rates for deflection into one interface or the other can be used for designing the interface, namely for prediction of the direction of further crack propagation.

Mixed-Mode Failure of Graphite/Epoxy Composites

2001 ◽  
Vol 123 (3) ◽  
pp. 371-376 ◽  
Author(s):  
M. A. Seif ◽  
M. Shahjahan
Keyword(s):  
Mixed Mode ◽  
Failure Modes ◽  
Crack Opening ◽  
Damage Zone ◽  
Theoretical Data ◽  
Opening Displacement ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Loading Axis ◽  
Mode Failure

An experimental study of the crack displacement and failure modes of graphite epoxyplates, having central cracks at different angles with the loading axis, was conducted. Due to this type of loading arrangement, the material was under mixed-mode loading condition (mode I and mode II). In this investigation, Moire´ Interferometry technique was employed to measure Crack Opening Displacement (COD) and Crack Shearing Displacement (CSD). Detailed studies were performed to investigate the effect of the crack angle on the strength reduction ratio, the damage zone, and the critical stress intensity factors. The comparison between the Linear Elastic Fracture Mechanics (LEFM) solution and the results obtained from this investigation showed a fair agreement between the theoretical data and the experimental ones. This confirms the validity of implementing the LEFM model for this type of materials.

HREM observation of dislocations near room temperature fractures in silicon

1988 ◽  
Vol 46 ◽  
pp. 892-893
Author(s):  
M. H. Rhee ◽  
W. A. Coghlan
Keyword(s):  
Cross Section ◽  
Room Temperature ◽  
Single Crystal Silicon ◽  
Dislocation Nucleation ◽  
Back Side ◽  
Ion Milling ◽  
Crystal Silicon ◽  
Flat Surfaces ◽  
Induced Fractures ◽  
Vicker’S Microhardness

Silicon is believed to be an almost perfectly brittle material with cleavage occurring on {111} planes. In such a material at room temperature cleavage is expected to occur prior to any dislocation nucleation. This behavior suggests that cleavage fracture may be used to produce usable flat surfaces. Attempts to show this have failed. Such fractures produced in semiconductor silicon tend to occur on planes of variable orientation resulting in surfaces with a poor surface finish. In order to learn more about the mechanisms involved in fracture of silicon we began a HREM study of hardness indent induced fractures in thin samples of oxidized silicon.Samples of single crystal silicon were oxidized in air for 100 hours at 1000°C. Two pieces of this material were glued together and 500 μm thick cross-section samples were cut from the combined piece. The cross-section samples were indented using a Vicker's microhardness tester to produce cracks. The cracks in the samples were preserved by thinning from the back side using a combination of mechanical grinding and ion milling.

Analysis of Silicon-On-Insulator Structures Formed By Oxygen Ion Implantation

1985 ◽  
Vol 43 ◽  
pp. 300-301
Author(s):  
N. Lewis ◽  
E. L. Hall ◽  
A. Mogro-Campero ◽  
R. P. Love
Keyword(s):  
Ion Implantation ◽  
Single Crystal ◽  
Single Crystal Silicon ◽  
Silicon Layer ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Dose ◽  
Crystal Silicon ◽  
Oxygen Ion ◽  
Oxygen Ion Implantation

The formation of buried oxide structures in single crystal silicon by high-dose oxygen ion implantation has received considerable attention recently for applications in advanced electronic device fabrication. This process is performed in a vacuum, and under the proper implantation conditions results in a silicon-on-insulator (SOI) structure with a top single crystal silicon layer on an amorphous silicon dioxide layer. The top Si layer has the same orientation as the silicon substrate. The quality of the outermost portion of the Si top layer is important in device fabrication since it either can be used directly to build devices, or epitaxial Si may be grown on this layer. Therefore, careful characterization of the results of the ion implantation process is essential.

Strain measurement by means of bend contour microscopy

1989 ◽  
Vol 47 ◽  
pp. 210-211
Author(s):  
Philip D. Hren
Keyword(s):  
Strain Measurement ◽  
Large Angle ◽  
Single Crystal Silicon ◽  
Convergent Beam Electron Diffraction ◽  
Zone Axis ◽  
Silicon Membrane ◽  
Crystal Silicon ◽  
Contour Pattern ◽  
Convergent Beam ◽  
Low Symmetry

The pattern of bend contours which appear in the TEM image of a bent or curled sample indicates the shape into which the specimen is bent. Several authors have characterized the shape of their bent foils by this method, most recently I. Bolotov, as well as G. Möllenstedt and O. Rang in the early 1950’s. However, the samples they considered were viewed at orientations away from a zone axis, or at zone axes of low symmetry, so that dynamical interactions between the bend contours did not occur. Their calculations were thus based on purely geometric arguments. In this paper bend contours are used to measure deflections of a single-crystal silicon membrane at the (111) zone axis, where there are strong dynamical effects. Features in the bend contour pattern are identified and associated with a particular angle of bending of the membrane by reference to large-angle convergent-beam electron diffraction (LACBED) patterns.

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

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