Pop-in effect as homogeneous nucleation of dislocations during nanoindentation

Lorenz, Dominik; Zeckzer, A.; Hilpert, Uwe; Grau, P.; Johansen, H.; Leipner, Hartmut S.

doi:10.1103/physrevb.67.172101

Cited by 315 publications

(185 citation statements)

References 17 publications

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“…This abrupt change during loading can be connected to two phenomena: (1) the transition regime from elastic to elasto-plastic deformation of the material [31] or (2) the fracture of the oxide film due to the indentation stress intensity and the brittleness of the film [32][33][34]. In case 1, Hertz's theory represented by the power law: L¼ Kh 3/2 , where K is a parameter related to the elastic modulus, must be verified before the pop-in event.…”

Section: Indentation Experimentsmentioning

confidence: 99%

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

Hemmouche¹,

Chicot²,

Amrouche³

et al. 2013

Materials Science and Engineering: A

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. a b s t r a c tThe elastic modulus of thin films can be directly determined by instrumented indentation when the indenter penetration does not exceed a fraction of the film thickness, depending on the mechanical properties of both film and substrate. When it is not possible, application of models for separating the contribution of the substrate is necessary. In this work, the robustness of several models is analyzed in the case of the elastic modulus determination of a porous aluminium oxide film produced by anodization of an aluminium alloy. Instrumented indentation tests employing a Berkovich indenter were performed at a nanometric scale, which allowed a direct determination of the film elastic modulus, whose value was found to be approximately 11 GPa. However, at a micrometric scale the elastic modulus tends toward the value corresponding to the substrate, of approximately 73 GPa. The objective of the present work is to apply different models for testing their consistency over the complete set of indentation data obtained from both classical tests in microindentation and the continuous stiffness measurement mode in nanoindentation. This approach shows the continuity between the two scales of measurement thus allowing a better representation of the elastic modulus variation between two limits corresponding to the substrate and film elastic moduli. Gao's function proved to be the best to represent the elastic modulus variation.

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Section: Indentation Experimentsmentioning

confidence: 99%

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

Hemmouche¹,

Chicot²,

Amrouche³

et al. 2013

Materials Science and Engineering: A

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“…Once the maximal shearing stress at the surface under the tip has reached a critical value, dislocation nucleation may take place which is related to the so-called pop-in in indention force-penetration curves on III±V semiconductors. [21,22] The response of a material during scratching can change drastically when a thin layer is added on the surface. For instance, for a given tip radius and by using the proper load, it is possible to remove selectively an oxide at the surface of a silicon wafer without generating dislocations or phase transformations.…”

Section: Semiconductor Nano-scratchingmentioning

confidence: 99%

Cleavage Fracture of Brittle Semiconductors from the Nanometre to the Centimetre Scale

et al. 2005

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The objective of this paper is to present the fundamental phenomena occurring during the scribing and subsequent fracturing process usually performed when preparing surfaces of brittle semiconductors. In the first part, an overview of nano‐scratching experiments of different semiconductor surfaces (InP, Si and GaAs) is given. It is shown how phase transformation can occur in Si under a diamond tip, how single dislocations can be induced in InP wafers and how higher scratching load of GaAs wafer leads to the apparition of a crack network below the surface. A nano‐scratching device, inside a scanning electron microscope (SEM), has been used to observe how spalling (crack and detachment of chips) and/or ductile formation of chips may happen at the semiconductor surface. In the second part cleavage experiments are described. The breaking load of thin GaAs (100) wafers is directly related to the presence of initial sharp cracks induced by scratching. By performing finite element modelling (FEM) of samples under specific loading conditions, it is found that the depth of the median crack below the scratch determines quantitatively the onset of crack propagation. By carefully controlling the position and measuring the force during the cleavage, it is demonstrated that crack propagation through a wafer can be controlled. Besides, the influence of the loading configuration on crack propagation and on the cleaved surface quality is explained.

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“…It is well known that, in nanoindentation measurements of such a specimen without pre-strain, plastic deformation occurs via homogeneous dislocation nucleation and subsequent rapid dislocation multiplication, which results in a discrete jump in loaddisplacement curves so-called "pop-in". 24,25) The similar phenomenon should occur also in the MCL during the bending. For the displacement-control measurement, which is the present case, the rapid dislocation multiplication causes load drop.…”

Section: Influence Of Hydrogen On Grain Boundariesmentioning

confidence: 91%

<i>In-situ</i> Microbending Tests of Ni–Cr Alloy during Cathodic Hydrogen Charging by Electrochemical Nanoindentation

et al. 2017

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To investigate hydrogen embrittlement susceptibility of an individual grain boundary, microcantilevers were fabricated on Ni-Cr bialloy surfaces by focused ion beam, and microbending tests were conducted during hydrogen charging by electrochemical nanoindentation. For microcantilevers fabricated across a twin boundary and inside a grain, no crack was formed by the bending both in air and during hydrogen charging. On the other hand, for microcantilevers fabricated across a random grain boundary, a crack was formed by the bending during hydrogen charging, whereas no crack was formed in air. Thus, it was identified that, for Ni-Cr bialloy, random grain boundaries are more susceptible to hydrogen than twin boundaries and crystalline planes. To validate these experimental results, slow strain-rate tensile tests were also performed, and subcracks of the fractured specimens were analyzed by electron beam back-scattering diffraction. In accordance with the microbending test results, subcracks were predominantly formed along random grain boundaries, but never along twin boundaries and inside grains. Higher hydrogen susceptibility of the random grain boundaries with lower cohesive energy (i.e., work for separation), smooth fracture surfaces without dimples or tear ridges, and no correlation between strain accumulation and subcrack formation indicate that hydrogen embrittlement of Ni-Cr bialloy is caused by decohesion mechanism, where hydrogen atoms lower cohesive energy at grain boundaries.

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Pop-in effect as homogeneous nucleation of dislocations during nanoindentation

Cited by 315 publications

References 17 publications

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

Cleavage Fracture of Brittle Semiconductors from the Nanometre to the Centimetre Scale

<i>In-situ</i> Microbending Tests of Ni–Cr Alloy during Cathodic Hydrogen Charging by Electrochemical Nanoindentation

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