Name: in situ time-dependent dielectric breakdown in the transmission electron microscope: a possibility to understand the failure mechanism in microelectronic devices
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Description: Watch this Scientific Journal Video about In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devi

The authors would like to thank R&#252;diger Rosenkranz and Sven Niese (Fraunhofer IKTS-MD) for their assistance in sample preparation, and Ude Hangen, Douglas Stauffer, Ryan Major and Oden Warren (Hysitron Inc.) for their technical support on the PI95 TEM holder. The support of the Center for Advancing Electronics Dresden (cfaed) and the Dresden Center for Nanoanalysis (DCN) at Technische Universit&#228;t Dresden is acknowledged as well.

1. Preparing the Sample for the Focused Ion Beam (FIB) Thinning (Figure 1)
<ol>
	<li>Cleave the full wafer into small chips (~ 10 mm by 10 mm) with a diamond scribe.</li>
	<li>Mark the positions of the &#8220;tip-to-tip&#8221; structure on the chips.</li>
	<li>Saw the chip with a dicing machine to obtain bars of 60 &#181;m by 2 mm size. The bar includes the &#8220;tip-to-tip&#8221; structure in the center.</li>
	<li>Glue the target bar on a Cu half ring using the super glue. Next, glue the bar on a Cu sample stage also...

<ol>
	<li>Edelstein, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Full+Copper+Wiring+in+a+Sub-0.25+&#181;m+CMOS+ULSI+Technology.">Full Copper Wiring in a Sub-0.25 &#181;m CMOS ULSI Technology.</a> IEDM Tech. Dig. , 773-776 (1997).</li><li>List, S., Bamal, M., Stucchi, M., Maex, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+global+view+of+interconnects.">A global view of interconnects.</a> Microelectron. Eng. 83 (11/12), 2200-2207 (2006).</li><li>Meindl, J. D., Davis, J. A., Zarkesh-Ha, P., Patel, C. S., Martin, K. P., Kohl, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interconnect+opportunities+for+gigascale+integration.">Interconnect opportunities for gigascale integration.</a> IBM J. Res. Develop. 46 (2/3), 245-263 (2002).</li><li>Zhang, X. F., Wang, Y. W., Im, J. H., Ho, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chip-Package+Interaction+and+Reliability+Improvement+by+Structure+Optimization+for+Ultralow-k+Interconnects+in+Flip-Chip+Packages.">Chip-Package Interaction and Reliability Improvement by Structure Optimization for Ultralow-k Interconnects in Flip-Chip Packages.</a> IEEE Trans. Device Mater. Reliab. 12 (2), 462-469 (2012).</li><li>Lee, K. D., Ogawa, E. T., Yoon, S., Lu, X., Ho, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electromigration+reliability+of+dual-damascene+Cu/porous+methylsilsesquioxane+low+k+interconnects.">Electromigration reliability of dual-damascene Cu/porous methylsilsesquioxane low k interconnects.</a> Appl. Phys. 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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+of+Time-Dependent+Dielectric+Breakdown+in+Copper+Metallization).">Modeling of Time-Dependent Dielectric Breakdown in Copper Metallization).</a> IEEE Trans. Device Mater. Reliab. 3 (2), 26-30 (2003).</li><li>Achanta, R. S., Plawsky, J. L., Gill, W. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+time+dependent+dielectric+breakdown+model+for+field+accelerated+low-k+breakdown+due+to+copper+ions.">A time dependent dielectric breakdown model for field accelerated low-k breakdown due to copper ions.</a> Appl. Phys. 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Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-situ+Study+of+the+TDDB-Induced+Damage+Mechanism+in+Cu/Ultra-low-k+Interconnect+Structures.">In-situ Study of the TDDB-Induced Damage Mechanism in Cu/Ultra-low-k Interconnect Structures.</a> Microelectron. Eng. In Press, (2014).</li><li>Liao, Z. Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+New+In+Situ+Microscopy+Approach+to+Study+the+Degradation+and+Failure+Mechanisms+of+Time-Dependent+Dielectric+Breakdown:+Set-Up+and+Opportunities.">A New In Situ Microscopy Approach to Study the Degradation and Failure Mechanisms of Time-Dependent Dielectric Breakdown: Set-Up and Opportunities.</a> Adv. Eng. Mater. 16 (5), 486-493 (2014).</li><li>Lee, Z., Meyer, J. 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The prerequisite of success in the TDDB experiment is good sample preparation, especially in the FIB milling process in the SEM. Firstly, a thick Pt layer on top of the &#8220;tip-to-tip&#8221; structure has to be deposited. The thickness and the size of the Pt layer can be adjusted by the SEM operator, but have to follow three principles: (1) The thickness and the size are enough to protect the target area from possible ion beam damage during the whole milling process; (2) There is still a relatively thick Pt layer (&#8...

Since Cu interconnects were firstly introduced into the ultra-large-scale integration (ULSI) technology in 1997 1, low-k and ultra-low-k (ULK) dielectrics have been adopted into the back-end-of-line (BEoL) as the insulating materials between on-chip interconnects. The combination of new materials, e.g., Cu for reduced resistance and low-k/ULK dielectrics for lower capacitance, overcomes the effects of increased resistance-capacitance (RC) delay caused by interconnect dimensional shrinkage 2, 3. However, this benefit was encroached by the continuing aggressive scaling of microelectronic devices in recent years. The use of low-k/ULK materials results in various challenges in the manufacturing process and for the product reliability, particularly if the interconnect pitch reaches about 100 nm or less 4-6.
TDDB refers to the physical failure mechanism of a dielectric material as a function of time under an electric field. The TDDB reliability test is usually carried out under accelerated conditions (elevated electrical field and/or elevated temperature).
The TDDB in on-chip interconnect stacks is one of the most critical failure mechanisms for the microelectronic devices, which has already raised intense concerns in the reliability community. It will continue to be in the spotlight of reliability engineers since ULK dielectrics with even weaker electrical and mechanical properties are being integrated into the devices in advanced technology nodes.
Dedicated experiments have been performed to investigate the TDDB failure mechanism 7-9, and a significant amount of effort has been invested to develop models which describe the relationship between electric field and lifetime of the devices 10-13. The existing studies benefit the community of reliability engineers in microelectronics; however, many challenges still exist and many questions still need to be answered in detail. For example, proven models to describe the physical failure mechanism and degradation kinetics in the TDDB process and the respective experimental verification are still lacking. As a particular need, a more appropriate model is needed to substitute the conservative &#8730;E-model 14.
As a very important part of the TDDB investigation, typical failure analysis is facing an unprecedented challenge, i.e., providing comprehensive and hard evidence to explain the physics of failure mechanisms and degradation kinetics. Apparently, inspecting millions of vias and meters of nanoscale Cu lines one by one and ex situ imaging the failure site is not the appropriate choice to hurdle this challenge, because it is very time consuming, and only limited information about the kinetics of the damage mechanism can be provided. Therefore, an urgent task has emerged to develop and to optimize experiments and to get a better procedure to study the TDDB failure mechanisms and degradation kinetics.
In this paper, we will demonstrate an in situ experimental methodology to investigate the TDDB failure mechanism in Cu/ULK interconnect stacks. A TEM with the ability of high quality imaging and chemical analysis is used to study the kinetic process at dedicated test structures. The in situ electrical test is integrated into the TEM experiment to provide an elevated electrical field to the dielectrics. A customized &#8220;tip-to-tip&#8221; structure, consisting of fully encapsulated Cu interconnects and insulated by a ULK material, is designed in the 32 nm CMOS technology node. The experimental procedure described here can also be extended to other structures in active devices.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Automatic Dicing Saw</td>
			<td>DISCO Kiru-Kezuru-Migaku Technologies</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scanning Electron Microscope</td>
			<td>Zeiss</td>
			<td>Zeiss Nvision 40</td>
			<td></td>
		</tr>
		<tr>
			<td>Picoindentor</td>
			<td>Hysitron</td>
			<td>Hysitron Pi95</td>
			<td></td>
		</tr>
		<tr>
			<td>Keithley SourceMeter</td>
			<td>Keithley</td>
			<td>Keithley 2602/237</td>
			<td></td>
		</tr>
		<tr>
			<td>Transmission Electron Microscope</td>
			<td>FEI</td>
			<td>FEI Tecnai F20</td>
			<td></td>
		</tr>
		<tr>
			<td>Transmission Electron Microscope</td>
			<td>Zeiss</td>
			<td>Zeiss Libra 200</td>
			<td></td>
		</tr>
	</tbody>
</table>

in situ time-dependent dielectric breakdown in the transmission electron microscope: a possibility to understand the failure mechanism in microelectronic devices

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. The aggressive scaling of feature sizes, both on devices and interconnects, leads to serious challenges to ensure the required product reliability. Standard reliability tests and post-mortem failure analysis provide only limited information about the physics of failure mechanisms and degradation kinetics. Therefore it is necessary to develop new experimental approaches and procedures to study the TDDB failure mechanisms and degradation kinetics in particular. In this paper, an in situ experimental methodology in the transmission electron microscope (TEM) is demonstrated to investigate the TDDB degradation and failure mechanisms in Cu/ULK interconnect stacks. High quality imaging and chemical analysis are used to study the kinetic process. The in situ electrical test is integrated into the TEM to provide an elevated electrical field to the dielectrics. Electron tomography is utilized to characterize the directed Cu diffusion in the insulating dielectrics. This experimental procedure opens a possibility to study the failure mechanism in interconnect stacks of microelectronic products, and it could also be extended to other structures in active devices.

Figure 4 shows bright field (BF) TEM images from an in situ test. There are partially breached TaN/Ta barriers and pre-existing Cu atoms in the ULK dielectrics before the electrical test (Figure 4A) due to extended storage in ambient. After only 376 sec at 40 V, the dielectric breakdown started and was accompanied with two major migration pathways of copper from the M1 metal, having a positive potential with reference to the ground side 15-16. The diffused Cu particle...

Watch this Scientific Journal Video about In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devi

In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devices

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. This paper demonstrates the procedure of an in situ TDDB experiment in the transmission electron microscope, which opens a possibility to study the failure mechanism in microelectronic products.

In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devices

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. ...

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Revealing Dynamic Processes of Materials in Liquids Using Liquid Cell Transmission Electron Microscopy

The recent development for in situ transmission electron microscopy, which allows imaging through liquids with high spatial resolution, has attracted significant interests across the research fields of materials science, physics, chemistry and biology. The key enabling technology is a liquid cell. We fabricate liquid cells with thin viewing windows through a sequential microfabrication process, including silicon nitride membrane deposition, photolithographic patterning, wafer etching, cell bonding, etc. A liquid cell with the dimensions of a regular TEM grid can fit in any standard TEM sample holder. About 100 nanoliters reaction solution is loaded into the reservoirs and about 30 picoliters liquid is drawn into the viewing windows by capillary force. Subsequently, the cell is sealed and loaded into a microscope for in situ imaging. Inside the TEM, the electron beam goes through the thin liquid layer sandwiched between two silicon nitride membranes. Dynamic processes of nanoparticles in liquids, such as nucleation and growth of nanocrystals, diffusion and assembly of nanoparticles, etc., have been imaged in real time with sub-nanometer resolution. We have also applied this method to other research areas, e.g., imaging proteins in water. Liquid cell TEM is poised to play a major role in revealing dynamic processes of materials in their working environments. It may also bring high impact in the study of biological processes in their native environment.

We have developed a self-contained liquid cell, which allows imaging through liquids using a transmission electron microscope. Dynamic processes of nanoparticles in liquids can be revealed in real time with sub-nanometer resolution.

The recent development for in situ transmission electron microscopy, which allows imaging through liquids with high spatial resolution, has attracted ...

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

Synchrotron radiation micro-tomography (SR&#181;T) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data acquisition times with high spatial resolution. In the electronics industry there is serious interest in performing failure analysis on 3D microelectronic packages, many which contain multiple levels of high-density interconnections. Often in tomography there is a trade-off between image resolution and the volume of a sample that can be imaged. This inverse relationship limits the usefulness of conventional computed tomography (CT) systems since a microelectronic package is often large in cross sectional area 100-3,600 mm2, but has important features on the micron scale. The micro-tomography beamline at the Advanced Light Source (ALS), in Berkeley, CA USA, has a setup which is adaptable and can be tailored to a sample&#39;s properties, i.e., density, thickness, etc., with a maximum allowable cross-section of 36 x 36 mm. This setup also has the option of being either monochromatic in the energy range ~7-43 keV or operating with maximum flux in white light mode using a polychromatic beam. Presented here are details of the experimental steps taken to image an entire 16 x 16 mm system within a package, in order to obtain 3D images of the system with a spatial resolution of 8.7 &#181;m all within a scan time of less than 3 min. Also shown are results from packages scanned in different orientations and a sectioned package for higher resolution imaging. In contrast a conventional CT system would take hours to record data with potentially poorer resolution. Indeed, the ratio of field-of-view to throughput time is much higher when using the synchrotron radiation tomography setup. The description below of the experimental setup can be implemented and adapted for use with many other multi-materials.

For this study synchrotron radiation micro-tomography, a non-destructive three-dimensional imaging technique, is employed to investigate an entire microelectronic package with a cross-sectional area of 16 x 16 mm. Due to the synchrotron&#39;s high flux and brightness the sample was imaged in just 3 min&#160;with an 8.7 &#181;m spatial resolution.

Synchrotron radiation micro-tomography (SR&#181;T) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data ...

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications of semiconductor materials. However, it is still under debate how the defect structure determines the band structure, and therefore, the recombination behavior of electron-hole pairs responsible for the optical and electrical properties of the extended defects. The present paper is a survey of procedures for the spatially resolved investigation of structural and of physical properties of extended defects in semiconductor materials with a scanning electron microscope (SEM). Representative examples are given for crystalline silicon. The luminescence behavior of extended defects can be investigated by cathodoluminescence (CL) measurements. They are particularly valuable because spectrally and spatially resolved information can be obtained simultaneously. For silicon, with an indirect electronic band structure, CL measurements should be carried out at low temperatures down to 5 K due to the low fraction of radiative recombination processes in comparison to non-radiative transitions at room temperature. For the study of the electrical properties of extended defects, the electron beam induced current (EBIC) technique can be applied. The EBIC image reflects the local distribution of defects due to the increased charge-carrier recombination in their vicinity. The procedure for EBIC investigations is described for measurements at room temperature and at low temperatures. Internal strain fields arising from extended defects can be determined quantitatively by cross-correlation electron backscatter diffraction (ccEBSD). This method is challenging because of the necessary preparation of the sample surface and because of the quality of the diffraction patterns which are recorded during the mapping of the sample. The spatial resolution of the three experimental techniques is compared.

The optical, electrical, and structural properties of dislocations and of grain boundaries in semiconductor materials can be determined by experiments performed in a scanning electron microscope. Electron microscopy has been used to investigate cathodoluminescence, electron beam induced current, and diffraction of backscattered electrons.

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications ...

Optical Trap Loading of Dielectric Microparticles In Air

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly scattered dielectric microparticles adhered to a glass substrate are momentarily detached using ultrasonic vibrations generated by a piezoelectric transducer (PZT). Then, the optical beam focused on a selected particle lifts it up to the optical trap while the vibrationally excited microparticles fall back to the substrate. A particle may be trapped at the nominal focus of the trapping beam or at a position above the focus (referred to here as the levitation position) where gravity provides the restoring force. After the measurement, the trapped particle can be placed at a desired position on the substrate in a controlled manner. 
In this protocol, an experimental procedure for selective optical trap loading in air is outlined. First, the experimental setup is briefly introduced. Second, the design and fabrication of a PZT holder and a sample enclosure are illustrated in detail. The optical trap loading of a selected microparticle is then demonstrated with step-by-step instructions including sample preparation, launching into the trap, and use of electrostatic force to excite particle motion in the trap and measure charge. Finally, we present recorded particle trajectories of Brownian and ballistic motions of a trapped microparticle in air. These trajectories can be used to measure stiffness or to verify optical alignment through time domain and frequency domain analysis. Selective trap loading enables optical tweezers to track a particle and its changes over repeated trap loadings in a reversible manner, thereby enabling studies of particle-surface interaction.

A protocol for launching and stably trapping selected dielectric microparticles in air is presented.

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly ...

A Method for Obtaining Serial Ultrathin Sections of Microorganisms in Transmission Electron Microscopy

Observing cells and cell components in three dimensions at high magnification in transmission electron microscopy requires preparing serial ultrathin sections of the specimen. Although preparing serial ultrathin sections is considered to be very difficult, it is rather easy if the proper method is used. In this paper, we show a step-by-step procedure for safely obtaining serial ultrathin sections of microorganisms. The key points of this method are: 1) to use the large part of the specimen and adjust the specimen surface and knife edge so that they are parallel to each other; 2) to cut serial sections in groups and avoid difficulty in separating sections using a pair of hair strands when retrieving a group of serial sections onto the slit grids; 3) to use a 'Section-holding loop' and avoid mixing up the order of the section groups; 4) to use a 'Water-surface-raising loop' and make sure the sections are positioned on the apex of the water and that they touch the grid first, in order to place them in the desired position on the grids; 5) to use the support film on an aluminum rack and make it easier to recover the sections on the grids and to avoid wrinkling of the support film; and 6) to use a staining tube and avoid accidentally breaking the support films with tweezers. This new method enables obtaining serial ultrathin sections without difficulty. The method makes it possible to analyze cell structures of microorganisms at high resolution in 3D, which cannot be achieved by using the automatic tape-collecting ultramicrotome method and serial block-face or focused ion beam scanning electron microscopy.

This study presents reliable and easy procedures for obtaining serial ultrathin sections of a microorganism without expensive equipment in transmission electron microscopy.

Observing cells and cell components in three dimensions at high magnification in transmission electron microscopy requires preparing serial ultrathin ...

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic glasses (MGs). Despite their amorphous nature, the identification of hyperfine interactions unveils faint structural modifications. For this purpose, we have employed two techniques that utilize nuclear resonance among nuclear levels of a stable 57Fe isotope, namely M&#246;ssbauer spectrometry and nuclear forward scattering (NFS) of synchrotron radiation. The effects of heat treatment upon (Fe2.85Co1)77Mo8Cu1B14 MG are discussed using the results of ex situ and in situ experiments, respectively. As both methods are sensitive to hyperfine interactions, information on structural arrangement as well as on magnetic microstructure is readily available. M&#246;ssbauer spectrometry performed ex situ describes how the structural arrangement and magnetic microstructure appears at room temperature after the annealing under certain conditions (temperature, time), and thus this technique inspects steady states. On the other hand, NFS data are recorded in situ during dynamically changing temperature and NFS examines transient states. The use of both techniques provides complementary information. In general, they can be applied to any suitable system in which it is important to know its steady state but also transient states.

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Here, we present a protocol to describe ex situ and in situ investigations of structural transformations in metallic glasses. We employed nuclear-based analytical methods which inspect hyperfine interactions. We demonstrate the applicability of M&#246;ssbauer spectrometry and nuclear forward scattering of synchrotron radiation during temperature-driven experiments.

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic ...

Single-Digit Nanometer Electron-Beam Lithography with an Aberration-Corrected Scanning Transmission Electron Microscope

We demonstrate extension of electron-beam lithography using conventional resists and pattern transfer processes to single-digit nanometer dimensions by employing an aberration-corrected scanning transmission electron microscope as the exposure tool. Here, we present results of single-digit nanometer patterning of two widely used electron-beam resists: poly (methyl methacrylate) and hydrogen silsesquioxane. The method achieves sub-5 nanometer features in poly (methyl methacrylate) and sub-10 nanometer resolution in hydrogen silsesquioxane. High-fidelity transfer of these patterns into target materials of choice can be performed using metal lift-off, plasma etch, and resist infiltration with organometallics.

We use an aberration-corrected scanning transmission electron microscope to define single-digit nanometer patterns in two widely-used electron-beam resists: poly (methyl methacrylate) and hydrogen silsesquioxane. Resist patterns can be replicated in target materials of choice with single-digit nanometer fidelity using liftoff, plasma etching, and resist infiltration by organometallics.

We demonstrate extension of electron-beam lithography using conventional resists and pattern transfer processes to single-digit nanometer dimensions by ...

Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites

In this work, an easy, low-cost, and widely applicable method was developed to improve the compatibility between the ceramic fillers and the polymer matrix by adding 3-aminopropyltriethoxysilane (KH550) as a coupling agent during the fabrication process of BaTiO3-P(VDF-CTFE) nanocomposites through solution casting. Results show that the use of KH550 can modify the surface of ceramic nanofillers; therefore, good wettability on the ceramic-polymer interface was achieved, and the enhanced energy storage performances were obtained by a suitable amount of the coupling agent. This method can be used to prepare flexible composites, which is highly desirable for the production of high-performance film capacitors. If an excessive amount of coupling agent is used in the process, the non-attached coupling agent can participate in complex reactions, which leads to a decrease in dielectric constant and an increase in dielectric loss.

Here, we demonstrate a simple and low-cost solution-casting process to improve the compatibility between the filler and the matrix of polymer-based nanocomposites using surface modified BaTiO3 fillers, which can effectively enhance the energy density of the composites.

In this work, an easy, low-cost, and widely applicable method was developed to improve the compatibility between the ceramic fillers and the polymer ...

In Situ Transmission Electron Microscopy with Biasing and Fabrication of Asymmetric Crossbars Based on Mixed-Phased a-VOx

Resistive switching crossbar architecture is highly desired in the field of digital memories due to low cost and high-density benefits. Different materials show variability in resistive switching properties due to the intrinsic nature of the material used, leading to discrepancies in the field because of underlying operation mechanisms. This highlights a need for a reliable technique to understand mechanisms using nanostructural observations. This protocol explains a detailed process and methodology of in&#160;situ nanostructural analysis as a result of electrical biasing using transmission electron microscopy (TEM). It provides visual and reliable evidence of underlying nanostructural changes in real time memory operations. Also included is the methodology of fabrication and electrical characterizations for asymmetric crossbar structures incorporating amorphous vanadium oxide. The protocol explained here for vanadium oxide films can be easily extended to any other materials in a metal-dielectric-metal sandwiched structure. Resistive switching crossbars are predicted to serve the programmable logic and neuromorphic circuits for next-generation memory devices, given the understanding of the operation mechanisms. This protocol reveals the switching mechanism in a reliable, timely, and cost-effective way in any type of resistive switching materials, and thereby predicts the device&#39;s applicability.

In Situ Transmission Electron Microscopy with Biasing and Fabrication of Asymmetric Crossbars Based on Mixed-Phased a-VOx

Presented here is a protocol for analyzing nanostructural changes during in&#160;situ biasing with transmission electron microscopy (TEM) for a stacked metal-insulator-metal structure. It has significant applications in resistive switching crossbars for the next generation of programmable logic circuits and neuromimicking hardware, to reveal their underlying operation mechanisms and practical applicability.