scholarly journals Influence of Growth Defects on the Corrosion Resistance of Sputter-Deposited TiAlN Hard Coatings

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 511 ◽  
Author(s):  
Panjan ◽  
Drnovšek ◽  
Gselman ◽  
Čekada ◽  
Panjan ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Electrochemical Impedance ◽  
Ion Beam ◽  
Hard Coatings ◽  
Growth Defects ◽  
Coating Morphology ◽  
Before And After ◽  
Sputter Deposited

In this work, the causes of porosity of TiAlN hard coatings sputter deposited on D2 tool steel were studied since its corrosion resistance is mainly affected by imperfections within the coating (e.g., pinholes, pores, crevices). The corrosion test was performed in a chlorine solution using electrochemical impedance spectroscopy. The coating morphology of growth defects before and after the exposure was studied by scanning electron microscopy (SEM), while focused ion beam (FIB) was used to make series of cross-sections through individual selected defects. We confirm that pitting corrosion is closely related to the through-thickness growth defects. It was also found that in the case of nodular defects, the intensity of corrosion depends on the shape of the seed.

scholarly journals Fabrication and Modeling of Recessed Traces for Silicon-Based Neural Microelectrodes

2020 ◽  
Author(s):  
Nicholas F Nolta ◽  
Pejman Ghelich ◽  
Martin Han
Keyword(s):  
Cross Sections ◽  
Focused Ion Beam ◽  
Electrochemical Impedance ◽  
Ion Beam ◽  
Intrinsic Stress ◽  
Insulation Material ◽  
Stress Concentrations ◽  
Insulation Materials ◽  
Neural Microelectrodes

AbstractChronically-implanted neural microelectrodes are powerful tools for neuroscience research and emerging clinical applications, but their usefulness is limited by their tendency to fail after months in vivo. One failure mode is the degradation of insulation materials that protect the conductive traces from the saline environment. Studies have shown that material degradation is accelerated by mechanical stresses, which tend to concentrate on raised topographies such as conducting traces. Therefore, to avoid raised topographies, we developed a fabrication technique that recesses (buries) the traces in dry-etched, self-aligned trenches. The depth of the trenches and the thickness of the traces are matched so that overlying insulation materials are flat, which, according to finite-element modeling, reduces stress concentrations in the insulation material. Here, we provide details on process optimization, modeling of intrinsic stress, and characterization using SEM, focused ion-beam cross sections, profilometry, and electrochemical impedance testing. The technique requires no extra masks, is easy to integrate with existing processes, and produces flatness within about 10 nm.

scholarly journals Influence of Growth Defects on the Oxidation Resistance of Sputter-Deposited TiAlN Hard Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 123
Author(s):  
Peter Panjan ◽  
Aljaž Drnovšek ◽  
Goran Dražić
Keyword(s):  
Oxidation Resistance ◽  
Cross Sections ◽  
Early Stage ◽  
Substrate Surface ◽  
Hard Coatings ◽  
Growth Defects ◽  
Compressive Stresses ◽  
Sputter Deposited ◽  
Titanium Diffusion

This paper reports the results of an investigation of the oxidation of a sputter-deposited TiAlN hard coating in air at temperatures of 800 and 850 °C for times ranging from 15 min to 2 h. The study is focused on the role of growth defects in the oxidation process. The mechanism of oxidation at the site of the defect was studied on cross-sections made by the consecutive sectioning of oxidized coatings with the FIB technique. We found that in the early stage of oxidation, the locally intense oxidation always starts at such defects. Although the growth defects reduce the oxidation resistance of the coating locally, we believe that they do not have a decisive influence on the global oxidation resistance of the coating. There are several reasons for this. The first is that the surface area covered by growth defects is relatively low (less than 1%). Secondly, the coating is permeable only at those defects that extend through the entire coating thickness. Thirdly, the permeability at the rim of some defects strongly depends on the density of pores at the rim of defects and how open they are. The size and density of such pores depend on the shape and size of topographical irregularities on the substrate surface (e.g., seeds, pits), which are responsible for the formation of growth defects. We also found that oxidation of the TiAlN coating is accelerated by oxygen and titanium diffusion through the pores formed by crystal grain growth in the outer alumina overlayer. Such pores are formed due to the compressive stresses in the Ti-rich oxide layer, which are caused by the large difference in molar volumes between the oxide and nitride phases.

An Study of Influence of Imperfections on the Delamination of Diamond-Like Carbon Films

2002 ◽  
Vol 719 ◽  
Author(s):  
Myoung-Woon Moon ◽  
Kyang-Ryel Lee ◽  
Jin-Won Chung ◽  
Kyu Hwan Oh
Keyword(s):  
Cross Sections ◽  
Focused Ion Beam ◽  
Imaging System ◽  
Ion Beam ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Glass Substrates ◽  
Atomic Force ◽  
Initiation And Propagation

AbstractThe role of imperfections on the initiation and propagation of interface delaminations in compressed thin films has been analyzed using experiments with diamond-like carbon (DLC) films deposited onto glass substrates. The surface topologies and interface separations have been characterized by using the Atomic Force Microscope (AFM) and the Focused Ion Beam (FIB) imaging system. The lengths and amplitudes of numerous imperfections have been measured by AFM and the interface separations characterized on cross sections made with the FIB. Chemical analysis of several sites, performed using Auger Electron Spectroscopy (AES), has revealed the origin of the imperfections. The incidence of buckles has been correlated with the imperfection length.

FIB Enhancement of Mechanically Polished Cross-sections

2019 ◽  
Author(s):  
Becky Holdford
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Resolution Imaging ◽  
Chemical Attack ◽  
Resolution Imaging ◽  
Scanning Electron

Abstract On mechanically polished cross-sections, getting a surface adequate for high-resolution imaging is sometimes beyond the analyst’s ability, due to material smearing, chipping, polishing media chemical attack, etc.. A method has been developed to enable the focused ion beam (FIB) to re-face the section block and achieve a surface that can be imaged at high resolution in the scanning electron microscope (SEM).

Yield Enhancement Study: Process Variation and Design Margins Leading to Timing Issues in the RAM

2000 ◽  
Author(s):  
Srikanth Perungulam ◽  
Scott Wills ◽  
Greg Mekras
Keyword(s):  
Cross Sections ◽  
Digital Signal Processor ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Random Access ◽  
Digital Signal ◽  
Yield Enhancement ◽  
Final Conclusion ◽  
Stage Separation ◽  
Study Process

Abstract This paper illustrates a yield enhancement effort on a Digital Signal Processor (DSP) where random columns in the Static Random Access Memory (SRAM) were found to be failing. In this SRAM circuit, sense amps are designed with a two-stage separation and latch sequence. In the failing devices the bit line and bit_bar line were not separated far enough in voltage before latching got triggered. The design team determined that the sense amp was being turned on too quickly. The final conclusion was that a marginal sense amp design, combined with process deviations, would result in this type of failure. The possible process issues were narrowed to variations of via resistances on the bit and bit_bar lines. Scanning Electron Microscope (SEM) inspection of the the Focused Ion Beam (FIB) cross sections followed by Transmission Electron Microscopy (TEM) showed the presence of contaminants at the bottom of the vias causing resistance variations.

scholarly journals Modification of Double Oxide Film Defects with the Addition of Mo to An Al-Si-Mg Alloy

2021 ◽  
Author(s):  
Qi Chen ◽  
W. D. Griffiths
Keyword(s):  
Liquid Metal ◽  
Oxide Film ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Spinel Phase ◽  
Ion Beam ◽  
Transmission Electron Microscopy Analysis ◽  
Double Oxide ◽  
Alloy Castings ◽  
Film Defect

AbstractIn this work, Mo was added into Al melt to reduce the detrimental effect of double-oxide film defect. An air bubble was trapped in a liquid metal (2L99), served as an analogy for double-oxide film defect in aluminum alloy castings. It was found that the addition of Mo significantly accelerated the consumption of the entrapped bubble by 60 pct after holding for 1 hour. 2 sets of testbar molds were then cast, with 2L99 and 2L99+Mo alloy, with a badly designed running system, intended to deliberately introduce double oxide film defects into the liquid metal. Tensile testing showed that, with the addition of Mo, the Weibull modulus of the Ultimate Tensile Strength and pct Elongation was increased by a factor of 2.5 (from 9 to 23) and 2 (from 2.5 to 4.5), respectively. The fracture surface of 2L99+Mo alloy testbars revealed areas of nitrides contained within bi-film defects. Cross-sections through those defects by Focused Ion Beam milling suggested that the surface layer were permeable, which could be as thick as 30 μm, compared to around 500 nm for the typical oxide film thickness. Transmission Electron Microscopy analysis suggested that the nitride-containing layer consisted of nitride particles as well as spinel phase of various form. The hypothesis was raised that the permeability of the nitride layers promote the reaction between the entrapped atmosphere in the defect and the surrounding liquid metal, reducing the defect size and decreasing their impact on mechanical properties.

scholarly journals Is a Zirconia Dental Implant Safe When It Is Available on the Market?

Ceramics ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 568-577 ◽  
Author(s):  
Frigan ◽  
Chevalier ◽  
Zhang ◽  
Spies
Keyword(s):  
Phase Transformation ◽  
Dental Implants ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Layer Growth ◽  
Transformation Toughening ◽  
High Fracture ◽  
Clinical Safety ◽  
Dynamic Fatigue

The market share of zirconia (ZrO2) dental implants is steadily increasing. This material comprises a polymorphous character with three temperature-dependent crystalline structures, namely monoclinic (m), tetragonal (t) and cubic (c) phases. Special attention is given to the tetragonal phase when maintained in a metastable state at room temperature. Metastable tetragonal grains allow for the beneficial phenomenon of Phase Transformation Toughening (PTT), resulting in a high fracture resistance, but may lead to an undesired surface transformation to the monoclinic phase in a humid environment (low-temperature degradation, LTD, often referred to as ‘ageing’). Today, the clinical safety of zirconia dental implants by means of long-term stability is being addressed by two international ISO standards. These standards impose different experimental setups concerning the dynamic fatigue resistance of the final product (ISO 14801) or the ageing behavior of a standardized sample (ISO 13356) separately. However, when evaluating zirconia dental implants pre-clinically, oral environmental conditions should be simulated to the extent possible by combining a hydrothermal treatment and dynamic fatigue. For failure analysis, phase transformation might be quantified by non-destructive techniques, such as X-Ray Diffraction (XRD) or Raman spectroscopy, whereas Scanning Electron Microscopy (SEM) of cross-sections or Focused Ion Beam (FIB) sections might be used for visualization of the monoclinic layer growth in depth. Finally, a minimum load should be defined for static loading to fracture. The purpose of this communication is to contribute to the current discussion on how to optimize the aforementioned standards in order to guarantee clinical safety for the patients.

scholarly journals In Situ Delineation Etch Reveals Subtle Detail in SEM Images of Ion Milled Cross Sections Enabling In-Fab 3-D Metrology and Characterization

2000 ◽  
Vol 8 (2) ◽  
pp. 36-39
Author(s):  
Clive Chandler
Keyword(s):  
Sample Preparation ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Automated System ◽  
Sem Images ◽  
Difficult Time ◽  
Device Structures ◽  
Wet Etch ◽  
Conventional Sample

Control of layer thickness is critically important in the manufacture of semiconductor devices. Cross-sectioning exposes device structures for direct examination but conventional sample preparation procedures are difficult, time consuming, and grossly destructive. Cross sections created by focused ion beam (FIB) milling are easier, faster, and less destructive but have not offered the clear layer delineation provided by etching in the conventional sample preparation process. A new gas etch capability (Delineation Etch™ from FEI Company) offers results that are equivalent to conventional wet-etch preparations in a fraction of the time from a single, automated system in the fab without destroying the wafer. The new etch process also has application in milling high-aspect-ratio holes to create contacts to buried metal layers, and in deprocessing devices to reveal silicon and polysilicon structures.

Oxidation of Alloy-X in Subcritical, Transition, and Supercritical Water

CORROSION ◽  
10.5006/3881 ◽  
2021 ◽  
Author(s):  
Zachary Karmiol ◽  
Dev Chidambaram
Keyword(s):  
Supercritical Water ◽  
Photoelectron Spectroscopy ◽  
Focused Ion Beam ◽  
Elevated Temperatures ◽  
Subcritical Water ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nickel Based Superalloy ◽  
Before And After

This work investigates the oxidation of a nickel based superalloy, namely Alloy X, in water at elevated temperatures: subcritical water at 261°C and 27 MPa, the transition between subcritical and supercritical water at 374°C and 27 MPa, and supercritical water at 380°C and 27 MPa for 100 hours. The morphology of the sample surfaces were studied using scanning electron microscopy coupled with focused ion beam milling, and the surface chemistry was investigated using X-ray diffraction, Raman spectroscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy before and after exposure studies. Surfaces of all samples were identified to comprise of a ferrite spinel containing aluminum.

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