Determination of the Elastic and Plastic Properties of Transversely Isotropic Thin Films on Substrates by Sharp Indentation

MRS Advances ◽  
2018 ◽  
Vol 3 (8-9) ◽  
pp. 445-450
Author(s):  
Zheng Zhi ◽  
T. A. Venkatesh
Keyword(s):  
Thin Films ◽  
Material Properties ◽  
Transversely Isotropic ◽  
Indentation Method ◽  
Plastic Properties ◽  
Response Characteristics ◽  
Functional Relationships ◽  
Thin Film System ◽  
Indentation Response

ABSTRACTA combination of dimensional analysis and finite element modeling was invoked to characterize the indentation behavior of transversely isotropic thin films on substrate materials. Through indentation simulations of over 13,500 combinations of properties for the thin film system, functional relationships that connect the indentation responses of the thin films with the elastic and plastic properties of the thin films were obtained. The forward algorithms that predict the indentation response characteristics from known material properties and the reverse algorithms that predict the material properties from known indentation responses were verified to be very accurate. Thus, the viability of using the indentation method to determine the elastic and plastic properties of transversely isotropic thin films on substrate materials was demonstrated.

A new method for mechanical testing of thin films: Application to aluminum

2009 ◽  
Vol 24 (4) ◽  
pp. 1353-1360
Author(s):  
T. Kruml ◽  
M. Stranyanek ◽  
R. Ctvrtlik ◽  
P. Bohac ◽  
T. Vystavel ◽  
...  
Keyword(s):  
Thin Films ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Accurate Determination ◽  
Film Surface ◽  
Strain Curve ◽  
New Method ◽  
Plastic Properties ◽  
Precise Knowledge

A new method for measuring plastic properties of thin films deposited on a substrate is presented. Micrometric cylindrical specimens with the axis perpendicular to the film surface were prepared by milling out the surrounding material using the focused ion beam technique. Such specimens were deformed by means of a nanoindenter outfitted with a flat diamond tip. An equivalent to the macroscopic compressive curve was obtained. Elastic modulus and hardness of the film were then measured using a Berkovich tip. The precise knowledge of the gage length and the independent measurement of elastic properties enable the accurate determination of the stress–strain curve. As compared with the results published in the literature on the specimens with the same dimensions, the studied material deforms less heterogeneously, probably as a consequence of the symmetric crystallographic orientation of the specimens.

On-Chip Structures for the Determination of the Dopant-Dependent Young’s Modulus of Heavily Phosphorus Doped Polysilicon With Stress Compensation

2010 ◽  
Author(s):  
E. Bassiachvili ◽  
J. R. Godin ◽  
P. Nieva ◽  
A. Khajepour
Keyword(s):  
Thin Films ◽  
Young’S Modulus ◽  
Material Properties ◽  
Young's Modulus ◽  
Direct Access ◽  
Film Material ◽  
Heavily Doped ◽  
Stress Compensation ◽  
On Chip

Accurate knowledge of thin-film material properties, such as Young’s modulus, is imperative in proper design and operation of MEMS devices. The use of on-chip devices allows direct access to the material properties as they are known to change with fabrication process, temperature as well as location within the wafer. Resonant and pull-in structures have been designed and modeled for the measurement of the Young’s modulus of heavily doped polysilicon thin films. The cantilever and clamped-clamped beams allow us to extract the Young’s modulus through observing the resonant frequency and pull-in voltage and cross-referencing the results. Mechanical actuation using a calibrated piezoelectric shaker for some devices and electrostatic actuation for others ensures that the structural effects, rather than the actuation technique, are responsible for the varying response at different temperatures. Optical readout will be used in order to reduce readout-associated errors, which can occur with purely electrical techniques at higher temperatures. However, electrical readout is also possible for some of the devices. The devices have been designed and fabricated using a customized 1-mask process. In this paper, we present the modeling and numerical simulations obtained for heavily doped polysilicon microstructures and will describe the method used for the determination of the Young’s modulus with stress compensation. Although the method described here has been used for heavily doped polysilicon thin films, it can be easily modified for the determination of Young’s modulus of other MEMS structural materials.

A method for interpreting the data from depth-sensing indentation instruments

1986 ◽  
Vol 1 (4) ◽  
pp. 601-609 ◽  
Author(s):  
M.F. Doerner ◽  
W.D. Nix
Keyword(s):  
Thin Films ◽  
Elastic Modulus ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Depth Sensing ◽  
Plastic Properties ◽  
Total Displacement ◽  
Exact Shape ◽  
Hardness Values

Depth-sensing indentation instruments provide a means for studying the elastic and plastic properties of thin films. A method for obtaining hardness and Young's modulus from the data obtained from these types of instruments is described. Elastic displacements are determined from the data obtained during unloading of the indentation. Young's modulus can be calculated from these measurements. In addition, the elastic contribution to the total displacement can be removed in order to calculate hardness. Determination of the exact shape of the indenter at the tip is critical to the measurement of both hardness and elastic modulus for indentation depths less than a micron. Hardness is shown to depend on strain rate, especially when the hardness values are calculated from the data along the loading curves.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

Determination of Stoichiometry of GaAs Component in (Gaas)Ge Epitaxially Grown Thin Films by Electron Microprobe X-Ray Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 264-265
Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Compound Semiconductors ◽  
Energy Dispersive Analysis ◽  
X Ray ◽  
Metastable Alloys ◽  
Lower Voltage

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.

Scanning-probe microscope analysis of optical thin films: A new analytical tool in a manufacturing environment

1994 ◽  
Vol 52 ◽  
pp. 1068-1069
Author(s):  
S. P. Sapers ◽  
R. Clark ◽  
P. Somerville
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Control ◽  
Scanning Probe Microscope ◽  
Scanning Probe ◽  
List Type ◽  
Manufacturing Environment ◽  
Physical Measurements ◽  
Probe Microscope

OCLI is a leading manufacturer of thin films for optical and thermal control applications. The determination of thin film and substrate topography can be a powerful way to obtain information for deposition process design and control, and about the final thin film device properties. At OCLI we use a scanning probe microscope (SPM) in the analytical lab to obtain qualitative and quantitative data about thin film and substrate surfaces for applications in production and research and development. This manufacturing environment requires a rapid response, and a large degree of flexibility, which poses special challenges for this emerging technology. The types of information the SPM provides can be broken into three categories:(1)Imaging of surface topography for visualization purposes, especially for samples that are not SEM compatible due to size or material constraints;(2)Examination of sample surface features to make physical measurements such as surface roughness, lateral feature spacing, grain size, and surface area;(3)Determination of physical properties such as surface compliance, i.e. “hardness”, surface frictional forces, surface electrical properties.

STEM and ELS Observation of Early Oxide Formation on the Surface of Cr Thin Films

1980 ◽  
Vol 38 ◽  
pp. 412-413
Author(s):  
Fumio Watari ◽  
J. M. Cowley
Keyword(s):  
Thin Films ◽  
Optical System ◽  
Room Temperature ◽  
Oxide Formation ◽  
Initial Nucleation ◽  
Diffraction Patterns ◽  
Relationship Of ◽  
Multiple Twinning ◽  
Moderately High Temperature

STEM coupled with the optical system was used for the investigation of the early oxidation on the surface of Cr. Cr thin films (30 – 1000Å) were prepared by evaporation onto the polished or air-cleaved NaCl substrates at room temperature and 45°C in a vacuum of 10−6 Torr with an evaporation speed 0.3Å/sec. Rather thick specimens (200 – 1000Å) with various preferred orientations were used for the investigation of the oxidation at moderately high temperature (600 − 1100°C). Selected area diffraction patterns in these specimens are usually very much complicated by the existence of the different kinds of oxides and their multiple twinning. The determination of the epitaxial orientation relationship of the oxides formed on the Cr surface was made possible by intensive use of the optical system and microdiffraction techniques. Prior to the formation of the known rhombohedral Cr2O3, a thin spinel oxide, probably analogous to γ -Al203 or γ -Fe203, was formed. Fig. 1a shows the distinct epitaxial growth of the spinel (001) as well as the rhombohedral (125) on the well-oriented Cr(001) surface. In the case of the Cr specimen with the (001) preferred orientation (Fig. 1b), the rings explainable by spinel structure appeared as well as the well defined epitaxial spots of the spinel (001). The microdif fraction from 20A areas (Fig. 2a) clearly shows the same pattern as Fig. Ia with the weaker oxide spots among the more intense Cr spots, indicating that the thickness of the oxide is much less than that of Cr. The rhombohedral Cr2O3 was nucleated preferably at the Cr(011) sites provided by the polycrystalline nature of the present specimens with the relation Cr2O3 (001)//Cr(011), and by further oxidation it grew into full coverage of the rest of the Cr surface with the orientation determined by the initial nucleation.

Interpreting Open- and Closed-Loop Transfer Relations Between Cardiorespiratory Parameters: Lessons Learned from a Computer Model of Beat-to-Beat Cardiovascular Regulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 237-240
Author(s):  
P. Hammer ◽  
D. Litvack ◽  
J. P. Saul
Keyword(s):  
Computer Model ◽  
Closed Loop ◽  
Computer Models ◽  
Cardiovascular Regulation ◽  
Cardiovascular Control ◽  
Lessons Learned ◽  
Multiple Systems ◽  
Response Characteristics ◽  
Similarities And Differences

Abstract:A computer model of cardiovascular control has been developed based on the response characteristics of cardiovascular control components derived from experiments in animals and humans. Results from the model were compared to those obtained experimentally in humans, and the similarities and differences were used to identify both the strengths and inadequacies of the concepts used to form the model. Findings were confirmatory of some concepts but contrary to some which are firmly held in the literature, indicating that understanding the complexity of cardiovascular control probably requires a combination of experiments and computer models which integrate multiple systems and allow for determination of sufficiency and necessity.

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