Characterization of Surface Layer of Silicon Wafer by Using Nano Indenter

Author(s):  
Yu-Li Sun ◽  
Dun-Wen Zuo ◽  
Yong-Wei Zhu ◽  
Feng Xu ◽  
Min Wang

Mechanical properties of the silicon wafer are evaluated by a nano indenter system with the continuous stiffness measurement (CSM) technique. Contact stiffness, hardness and elastic modulus of the silicon wafer are continuously measured during the loading in an indentation test. The results show that when the contact depth is between 20 and 32 nm, its contact stiffness is linear with the contact depth, and its hardness and elastic modulus keep constant at 10.2 GPa and 140.3 GPa respectively, which belong to the oxide coating of the silicon wafer. When the contact depth is between 32 and 60 nm, its contact stiffness is not linear with the contact depth, and the hardness and elastic modulus increase rapidly with the contact depth, because they are affected by the bulk material. When the contact depth is over 60 nm, the contact stiffness of the silicon wafer is linear with the contact depth again, and the hardness and elastic modulus keep constant at 12.5 GPa and 165.6 GPa respectively, which belong to the silicon wafer, the bulk material.

2016 ◽  
Vol 6 (4) ◽  
pp. 1089-1092
Author(s):  
L. Aminallah ◽  
S. Habibi

The determination of the performance of materials requires the characterization of materials at scales: macro, micro and nanoscale. Among the most common experimental methods one can find the instrumented indentation test for determining the contact stiffness and contact depth and analyzing the characteristic curve by nanoindentation load on the penetration of the indentor. Through statistical processing of the experimental results, the rigidity of contact on the contact depth is investigated, depending on the indentation load, for bronze, brass and copper. A mathematical model is adopted to describe the polynomial regression by the method of least squares growth rigidity with one or more geometric parameters representative of the size of the footprint. This study allows us to identify factors that influence the rigidity of the materials examined and the sensitivity of the used indenters.


2005 ◽  
Vol 20 (10) ◽  
pp. 2660-2669 ◽  
Author(s):  
J. Menčík ◽  
G. Rauchs ◽  
J. Bardon ◽  
A. Riche

When determining elastic modulus and hardness of viscoelastic-plastic materials by depth-sensing indentation, one must respect their specific response. In the monotonic load-unload testing mode, the unloading should be preceded by a dwell mitigating the influence of the delayed deforming. The continuous stiffness measurement (CSM) mode, with a small harmonic signal added to the basic monotonic load, enables continuous measurement of harmonic contact stiffness and mechanical properties as a function of depth. However, the contact depth and area in this mode actually depend on the slow (monotonic) component of the loading and should be determined not from the harmonic contact stiffness but from the unloading stiffness; otherwise, the calculated elastic modulus and mean contact pressure will be incorrect. This paper provides the formulae for these calculations, defines special characteristics—such as apparent dynamic hardness and the index of sensitivity to harmonic loading—and shows how to improve results by smoothing the harmonic stiffness curve. The proposed methods are illustrated through nanoindentation tests of polymethyl methacrylate.


2002 ◽  
Vol 17 (9) ◽  
pp. 2227-2234 ◽  
Author(s):  
M. Martin ◽  
M. Troyon

The fundamental relations used in the analysis of nanoindentation load–displacement data to determine elastic modulus and hardness are based on Sneddon's solution for indentation of an elastic half-space by rigid axisymmetric indenters. It has been recently emphasized that several features that have important implications for nanoindentation measurements are generally ignored. The first one concerns the measurement of the contact depth, which is actually determined by using a constant value ε = 0.75 for the geometry of a Berkovich indenter and for any kind of material, whereas the reality is that ε is a function of the power law exponent deduced from the analysis of the unloading curve. The second feature concerns the relation between contact stiffness, elastic modulus, and contact area, in which a correction factor γ larger than unity is usually ignored leading to a systematic overestimation of the area function and thus to errors in the measured hardness and modulus. Experimental measurements on fused quartz are presented that show the variation of ε with the geometry of the tip–sample contact; that is to say with the contact depth, as well as the existence of the correction factor γ, as predicted in some recent articles. Effects of both ε and γ on harness and modulus measurements are also shown.


Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 97 ◽  
Author(s):  
Wai Yeong Huen ◽  
Hyuk Lee ◽  
Vanissorn Vimonsatit ◽  
Priyan Mendis

The determination of elastic modulus (E) and hardness (H) relies on the accuracy of the contact area under the indenter tip, but this parameter cannot be explicitly measured during the nanoindentation process. This work presents a new approach that can derive the elastic modulus (E) and contact depth (hc) based on measured experiment stiffness using the continuous-stiffness-measurement (CSM) method. To achieve this, an inverse algorithm is proposed by incorporating a set of stiffness-based relationship functions that are derived from combining the dimensional analysis approach and computational simulation. This proposed solution considers both the sink-in and pile-up contact profiles; therefore, it provides a more accurate solution when compared to a conventional method that only considers the sink-in contact profile. While the proposed solution is sensitive to Poisson’s ratio (ν) and the equivalent indentation conical angle (θ), it is not affected by material plasticity, including yield strength (σy) and work hardening (n) for the investigated range of 0.001 < σy/E < 0.5. The proposed stiffness-based approach can be used to consistently derive elastic modulus and hardness by using stiffness and the load-and-unload curve measured by the continuous-stiffness-measurement (CSM) method.


2008 ◽  
Vol 375-376 ◽  
pp. 52-56 ◽  
Author(s):  
Yu Li Sun ◽  
Dun Wen Zuo ◽  
Duo Sheng Li ◽  
Rong Fa Chen ◽  
Min Wang

Hardness, elastic modulus and scratch resistance of single silicon wafer are measured by nanoindentation and nanoscratching using a nanoindenter. Fracture toughness is measured by indentation using a Vickers indenter. The results show that the hardness and elastic modulus at a peak indentation depth of 100 nm are 12.6 and 166.5 GPa respectively. These values reflect the properties of the silicon wafer, the bulk material. The fracture toughness value of the silicon wafer is 0.74 Mpa·m1/2. The material removal mechanisms are seen to be directly related to the normal force on the tip. The critical load and scratch depth estimated from the scratch depth profile after the scratching and the friction profile are 138.64 mN and 54.63 nm respectively. If the load and scratch depth are under the critical values, the silicon wafer will undergo plastic flow rather than fracture. The critical scratch depth is different from that calculated from the formula of critical-depth-of-cut described by Bifnao et al and some reasons are given.


1999 ◽  
Vol 594 ◽  
Author(s):  
T. A. Rawdanowicz ◽  
J. Sankar ◽  
J. Narayan ◽  
V. Godbole

AbstractThe hardnesses and elastic moduli of aluminum nitride (AIN) and titanium nitride (TiN) sub-micron thin films pulsed laser deposited (PLD) on silicon (111) were measured using nanoindentation based on a continuous stiffness measurement (CSM) technique. Thin film thicknesses, based on profile measurements of simultaneously grown step samples, are 210 nm and 180 nm with surface roughnesses of 12 nm and 2 nm for AlN and TiN, respectively. X-ray diffraction showed AlN as a highly textured polycrystalline AlN wurzite structure with a (0001) orientation and TiN as a cubic structure with a (111) orientation. The CSM technique provided hardness and elastic modulus as a function of depth. Finite element modeling (FEM) aided in determining the optimum indenter contact depth at which the thin films behaved as a semi-infinite solid with negligible substrate induced artifacts. Hardnesses of these AlN and TiN thin films were, determined analytically, 25 GPa and 33 GPa, as compared to FEM results of 24 GPa and 30 GPa, respectively. The elastic moduli measured 320 GPa and 370 GPa for these AlN and TiN thin films, respectively.


2013 ◽  
Vol 456 ◽  
pp. 545-548
Author(s):  
Xue Mei Liu ◽  
Xiao Yan Song ◽  
Hai Bin Wang ◽  
Yao Wang ◽  
Yang Gao ◽  
...  

The nanocrystalline WC-Co bulk material with a relative density of 98.5% was prepared by combing in-situ reduction and carbonization reactions and spark plasma sintering method. Using continuous stiffness measurement method in the nanoindentation technique, the high precision modulus and hardness of the material were measured.


2009 ◽  
Vol 24 (3) ◽  
pp. 653-666 ◽  
Author(s):  
G.M. Pharr ◽  
J.H. Strader ◽  
W.C. Oliver

Experiments were performed on a (100) copper single crystal to examine the influences that small displacement oscillations used in continuous stiffness measurement techniques have on hardness and elastic-modulus measurements in nanoindentation experiments. For the commonly used 2-nm oscillation, significant errors were observed in the measured properties, especially the hardness, at penetration depths as large as 100 nm. The errors originate from the large amount of dynamic unloading that occurs in materials like copper that have high contact stiffness resulting from their high modulus-to-hardness ratios. A simple model for the loading and unloading behavior of an elastic–plastic material is presented that quantitatively describes the errors and can be used to partially correct for them. By correcting the data in accordance with model and performing measurements at smaller displacement oscillation amplitudes, the errors can be reduced. The observations have important implications for the interpretation of the indentation size effect.


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