Continuous electrical in situ contact area measurement during instrumented indentation

2008 ◽  
Vol 23 (9) ◽  
pp. 2480-2485 ◽  
Author(s):  
Lei Fang ◽  
Christopher L. Muhlstein ◽  
James G. Collins ◽  
Amber L. Romasco ◽  
Lawrence H. Friedman
Keyword(s):  
Contact Area ◽  
Dynamic Properties ◽  
Electrical Contact ◽  
Area Measurement ◽  
Analysis Method ◽  
Instrumented Indentation ◽  
Current Voltage ◽  
Indentation Tests

The primary tool for mechanical characterization of surfaces and films is instrumented indentation using the Oliver-Pharr data analysis method. However, this method measures contact area between the indenter and sample indirectly, thus confounding instrumented indentation tests when characterizing dynamic properties, thin films, and materials that “pileup” around the indenter. Here, we demonstrate an electrical technique to continuously measure the in situ contact area by relating nonlinear electrical contact current–voltage (I–V) curves to the instantaneous contact area. Using this approach, we can obtain hardness as a continuous function of applied force.

Augmented instrumented indentation using nonlinear electrical contact current-voltage curves

2009 ◽  
Vol 24 (5) ◽  
pp. 1820-1832
Author(s):  
Lei Fang ◽  
Christopher L. Muhlstein ◽  
Amber L. Romasco ◽  
James G. Collins ◽  
Lawrence H. Friedman
Keyword(s):  
Contact Area ◽  
Electrical Contact ◽  
Area Measurement ◽  
Instrumented Indentation ◽  
Area Measure ◽  
Current Voltage ◽  
Loading Tests ◽  
Contact Response ◽  
Simple Summation

An electrical technique was recently developed to measure the in situ contact area continuously during instrumented indentation by simultaneously monitoring electrical contact response between a conductive indenter tip and a conductive sample. This technique has the potential to overcome limitations of the Oliver-Pharr method caused by the lack of a direct contact area measurement. However, the electrical contact current-voltage (I-V) curves measured from the technique were nonlinear, posing a significant challenge to inferring accurate in situ contact areas. To overcome this challenge and extend the electrical technique to more applications, various I-V curve analysis methods were investigated for their abilities to infer in situ contact area and hardness. Annealed Cu was indented using both linear and exponential loading tests. When analyzing the resulting data, the feasibility of each method was evaluated and the optimal methods to calculate the in situ contact area and hardness were determined. It was found that a simple summation of the absolute values of area under I-V curves or the area under I-V curves at positive voltages yielded the most robust area measure, whereas error in the inferred contact area was systematic and primarily from velocity dependence of the I-V response.

Instrumented indentation microscope applied to the elastoplastic indentation contact mechanics of coating/substrate composites

2009 ◽  
Vol 24 (6) ◽  
pp. 1950-1959 ◽  
Author(s):  
N. Hakiri ◽  
A. Matsuda ◽  
M. Sakai
Keyword(s):  
Contact Area ◽  
Film Coating ◽  
Instrumented Indentation ◽  
Thin Film Coating ◽  
Composite Systems ◽  
Indentation Tests ◽  
Film Substrate ◽  
Contact Parameters

In instrumented indentation tests for a thin film coating on a substrate (film/substrate composite), it is well known that the substrate-affected contact area estimated through conventional approximations includes significant uncertainties, leading to a crucial difficulty in determining the elastic modulus and the contact hardness. To overcome this difficulty, an instrumented indentation microscope that enables researchers to make an in situ determination of the contact area is applied to an elastoplastic film on substrates having various values of their elastic moduli. Using the indentation microscope, the substrate-affected indentation contact parameters including contact hardness of the film/substrate composites are determined directly as well as quantitatively without any undesirable assumptions and approximations associated with the contact area estimate. The effect of a stiffer substrate on the contact profile of impression is significant, switching the profile from sinking in to piling up during penetration, and resulting in the substrate-affected contact hardness being highly enhanced at deeper penetrations. Through the present experimental study, it is demonstrated how efficient that instrumented indentation microscopy is in determining the substrate-affected elastoplastic contact parameters of film/substrate composite systems.

Fabrication and Characterization of GaAs Tunnel Diode and ErAs Nanoparticles Enhanced GaAs Tunnel Diode for Multijunction Solar Cell

2014 ◽  
Vol 1602 ◽  
Author(s):  
Tomah Sogabe ◽  
Yasushi Shoji ◽  
Mitsuyoshi Ohba ◽  
Naito Shunya ◽  
Naoya Miyashita ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Contact Area ◽  
Tunnel Diode ◽  
Enhancement Effect ◽  
Peak Current Density ◽  
Gaas Sample ◽  
Load Line ◽  
Current Voltage ◽  
Fabrication And Characterization

ABSTRACTWe report here the fabrication and characterization of GaAs tunnel diode (TD) and ErAs nanoparticles (Nps) enhanced GaAs TD. Four GaAs TDs with different contact area were fabricated by using MOCVD. We found extremely high peak current density of ∼250A/cm2 for the TD with r=0.25mm contact area. Moreover a hysteresis loop was appeared during sweeping up and sweeping down the external voltage. A ‘vector load line model’ was proposed to explain the origin of the shape of the hysteresis loop and the onset of the bistability occurred at the intersect of the loadline and the current-voltage (I-V) curve of TD. Meanwhile, we have grown ErAs Nps on GaAs(100) surface by using MBE and succeeded in overgrowth of GaAs after ErAs deposition. GaAs(p+)/ErAs(Nps)/GaAs(n+) TDs were fabricated and characterized. We found the GaAs sample containing 70s deposition of ErAs showed the best TD behavior. No TD behavior was observed for the sample without addition of ErAs Nps, clearly indicating the strong tunneling enhancement effect from ErAs Nps.

Local Mechanical Characterization of Human Teeth by Instrumented Indentation

2010 ◽  
Vol 89-91 ◽  
pp. 751-756 ◽  
Author(s):  
Ilaria Cappelloni ◽  
Paolo Deodati ◽  
Roberto Montanari ◽  
Andrea Moriani
Keyword(s):  
Mechanical Characteristics ◽  
Mechanical Characterization ◽  
Damping Factor ◽  
Good Resolution ◽  
Instrumented Indentation ◽  
Mechanical Spectroscopy ◽  
Human Teeth ◽  
Indentation Tests ◽  
Cylindrical Punch

The mechanical characteristics of dentine have been investigated on local scale by micro-hardness and instrumented indentation tests. FIMEC, an indentation technique employing a cylindrical punch, permitted measurements of elastic modulus, yield stress, stress-relaxation and creep. The punch diameter (Φ = 0.5 mm) is much larger than the tubule size thus data are not so largely scattered as in micro- and nano-indentation tests but, at the same time, is small enough to guarantee a good resolution in mapping the mechanical properties in different tooth positions. The results are in agreement with literature data obtained by means of various experimental techniques. Furthermore, through tests of mechanical spectroscopy carried out on bar-shaped samples (13 mm x 4 mm x 0.8 mm) the dynamic modulus and the damping factor Q-1 have been measured.

Fabrication and Characterization of Copper Oxide Resistive Memory Devices

2011 ◽  
Vol 1337 ◽  
Author(s):  
S.M. Bishop ◽  
B.D. Briggs ◽  
Z.P. Rice ◽  
S. Addepalli ◽  
N.R. McDonald ◽  
...  
Keyword(s):  
Copper Oxide ◽  
Electrical Contact ◽  
Switching Behavior ◽  
Memory Devices ◽  
Plasma Oxidation ◽  
Resistive Memory ◽  
Oxide Interface ◽  
Bipolar Switching ◽  
Current Voltage

ABSTRACTThree synthesis techniques have been explored as routes to produce copper oxide for use in resistive memory devices (RMDs). The major results and their impact on device current-voltage characteristics are summarized. The majority of the devices fabricated from thermally oxidized copper exhibited a diode-like behavior independent of the top electrode. When these devices were etched to form mesa structures, bipolar switching was observed with set voltages <2.5 V, reset voltages <(-1) V and ROFF/RON ∼103-104. Bipolar switching behavior was also observed for devices fabricated from copper oxide synthesized by RT plasma oxidation (ROFF/RON up to 108). Voiding at the copper-copper oxide interface occurred in films produced by thermal and plasma oxidation performed at ≥200°C. The copper oxide synthesized by reactive sputtering had large areas of open volume in the microstructure; this resulted in short circuited devices because of electrical contact between the bottom and top electrodes. The results for fabricating copper oxide into ≤100 nm features are also discussed.

Effects of Particle Concentration in CMP

2001 ◽  
Vol 671 ◽  
Author(s):  
Wonseop Choi ◽  
Seung-Mahn Lee ◽  
Rajiv K. Singh
Keyword(s):  
Friction Force ◽  
Contact Area ◽  
Particle Concentration ◽  
Surface Coverage ◽  
Force Measurement ◽  
Solid Loading ◽  
Friction Forces ◽  
Lateral Friction

ABSTRACTThis paper reports on characterization of the surface coverage of particles by in-situ lateral friction force measurement during chemical mechanical polishing. The lateral friction force apparatus was made to operate close to real CMP conditions. For these experiments a sapphire wafer of constant surface roughness was used. For both 2psi and 4psi down force we observed increase in lateral friction forces with increasing solid loading. The lateral friction forces have been found to be significantly dependent on the contact area at the wafer-pad-slurry interface, thus showing that in-situ dynamic friction force changes in the surface coverage of particles. From these results, we conclude that the enhancement of frictional force is due to increased contact area at the wafer-pad-slurry interfaces. The lateral friction force measurement can provide an understanding of wafer-pad-slurry interactions.

Thermal Transport Measurements of Nanowire-Substrate Interfaces

2008 ◽  
Author(s):  
Monalisa Mazumder ◽  
Theodorian Borca-Tasciuc
Keyword(s):  
Thermal Resistance ◽  
Thermal Transport ◽  
Experimental Approach ◽  
Electrical Contact ◽  
Electrically Conductive ◽  
Interface Thermal Resistance ◽  
Current Voltage ◽  
Afm Cantilever ◽  
Topographic Imaging

An AFM based method for characterization of thermal transport properties of electrically conductive individual nanowires and nanowire-substrate interfaces has been developed. Nanostructures are located by topographic imaging in regular tapping mode and are then subsequently probed by an AFM cantilever tip, with a conductive coating thus establishing electrical contact at different positions on the nanowire followed by current-voltage data acquisition. This experimental approach can be implemented for a system with nanostructures in contact with the surface and, in the other case, suspended between electrodes. These configurations allow for characterization of both thermal conductivity and nano-interface thermal resistance. This work presents the technique along with the subsequent measurements of nano-interface thermal resistance of nanowire-substrate junction using the aforesaid technique.

Demonstration of Defect-Induced Limitations on the Properties of Au/3C-SiC Schottky Barrier Diodes

2009 ◽  
Vol 156-158 ◽  
pp. 331-336 ◽  
Author(s):  
Jens Eriksson ◽  
Ming Hung Weng ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
Stefano Leone ◽  
...  
Keyword(s):  
Contact Area ◽  
Schottky Diodes ◽  
Electrical Current ◽  
Contact Radius ◽  
Conductive Atomic Force Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage ◽  
Capacitance Voltage

The electrical current-voltage (I-V) and capacitance-voltage (C-V) characteristics of Au/3C-SiC Schottky diodes were studied as a function of contact area. The results were correlated to defects in the 3C-SiC, which were studied and quantified by conductive atomic force microscopy (C-AFM). A method based on C-AFM was introduced that enables current-voltage characterization of diodes of contact radius down to 5 µm, which consequently allows the extraction of diode parameters for Schottky diodes of very small contact area.

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