A Novel Sample Preparation Method for Frontside Inspection of GaN Devices after Backside Analysis

Frontside die inspection by Scanning Electron Microscopy (SEM) is critical to investigate failures that appear dispersed over the GaN die surface and that will be very difficult to localize by the typical Focus Ion Beam (FIB) or Transmission Electron Microscopy (TEM) analysis. Frontside sample preparation is; however, extremely challenging if the device was already subjected to sample preparation for backside Photo Emission Microscopy (PEM). In this paper, a novel sample preparation method is presented where all front side layers are removed and only the 5μm GaN die is left for inspection.

A New Delayering Application Workflow in Advanced 5nm Technology Device with Xenon Plasma Focus Ion Beam Microscopy

In semiconductor industry, planer analysis is important in many applications such as Passive Voltage Contrast (PVC) and sample preparation for nanoprobing. In order to achieve successful results on the planer surface analysis, a proper delayering technique is critical. As the thickness of metal line, via of Back-End-of Line (BEOL) and contact layer are getting thinner in advanced nodes, we observed convention hand polishing is facing major challenge in endpointing at exactly targeted layer and specific Region of Interest (ROI). In addition, Cobalt process starting from 5nm node brings additional challenges. Cobalt tends to be oxidized easily which becomes not friendly for nanoprobing. The alternative solution to produce good planar surface is to use Plasma Focus Ion Beam (PFIB) technique with patented DX gas assisted. PFIB changes the convention FA workflow and has been proven that the new workflow improves the efficiency of planar failure analysis such as PVC and nanoprobing sample preparation.

Design of SiC-Doped Piezoresistive Pressure Sensor for High-Temperature Applications

Within these studies the piezoresistive effect was analyzed for 6H-SiC and 4H-SiC material doped with various elements: N, B, and Sc. Bulk SiC crystals with a specific concentration of dopants were fabricated by the Physical Vapor Transport (PVT) technique. For such materials, the structures and properties were analyzed using X-ray diffraction, SEM, and Hall measurements. The samples in the form of a beam were also prepared and strained (bent) to measure the resistance change (Gauge Factor). Based on the results obtained for bulk materials, piezoresistive thin films on 6H-SiC and 4H-SiC substrate were fabricated by Chemical Vapor Deposition (CVD). Such materials were shaped by Focus Ion Beam (FIB) into pressure sensors with a specific geometry. The characteristics of the sensors made from different materials under a range of pressures and temperatures were obtained and are presented herewith.

Mitigating the Agglomeration of Nanofiller in a Mixed Matrix Membrane by Incorporating an Interface Agent

Nanodiamonds (ND) have recently emerged as excellent candidates for various applications including membrane technology due to their nanoscale size, non-toxic nature, excellent mechanical and thermal properties, high surface areas and tuneable surface structures with functional groups. However, their non-porous structure and strong tendency to aggregate are hindering their potential in gas separation membrane applications. To overcome those issues, this study proposes an efficient approach by decorating the ND surface with polyethyleneimine (PEI) before embedding it into the polymer matrix to fabricate MMMs for CO2/N2 separation. Acting as both interfacial binder and gas carrier agent, the PEI layer enhances the polymer/filler interfacial interaction, minimising the agglomeration of ND in the polymer matrix, which is evidenced by the focus ion beam scanning electron microscopy (FIB-SEM). The incorporation of PEI into the membrane matrix effectively improves the CO2/N2 selectivity compared to the pristine polymer membranes. The improvement in CO2/N2 selectivity is also modelled by calculating the interfacial permeabilities with the Felske model using the gas permeabilities in the MMM. This study proposes a simple and effective modification method to address both the interface and gas selectivity in the application of nanoscale and non-porous fillers in gas separation membranes.

Isotropic 3D electron microscopy reference library of whole cells and tissues

SummaryUnderstanding cellular architecture is essential for understanding biology. Electron microscopy (EM) uniquely visualizes cellular structure with nanometer resolution. However, traditional methods, such as thin-section EM or EM tomography, have limitations inasmuch as they only visualize a single slice or a relatively small volume of the cell, respectively. Here, we overcome these limitations by imaging whole cells and tissues with enhanced Focus Ion Beam Scanning Electron Microscopy (FIB-SEM) in high resolution with month-long acquisition duration. We use this approach to generate reference 3D image datasets at 4-nm isotropic voxels for ten different examples, including cultured cells (cancer, macrophages, and T-cells) as well as tissues (mouse pancreatic islets and the Drosophila fan-shaped body). We open access to all datasets in OpenOrganelle, an interactive web platform that allows accessing both the original 3D EM data, and subsequent organelle segmentation. Together, these data will serve as a reference library to explore comprehensive quantification of whole cells and their constituents, thus addressing questions related to cell identities, cell morphologies, cell-cell interactions, as well as intracellular organelle organization and structure.

Experimental Investigation of the Mechanical and Surface Properties of Sub-Micron Carbon Spheres

This study investigates the mechanical and surface properties of spherical carbon particles. Sub-micrometer carbon spheres were previously used as oil additives to improve the tribological performance of oils, and as anode material to enhance the storage of rechargeable lithium-ion batteries. In the current work, internal structure and chemical analysis of these carbon sphere particles was conducted via focus ion beam scanning electron microscopy, and the results revealed that the carbon sphere particles are pure carbon particles with a solid internal structure. Atomic force microscopy (AFM) and nano-indenter were utilized to explore the mechanical properties (hardness and elastic modulus) of carbon sphere particles. The obtained results showed that the carbon spheres have an elastic modulus in the range of 10 to 42 GPa, while their hardness is in the range of 0.5 to 2.6 GPa. Besides, the AFM scans confirmed that the carbon particles are entirely separated and devoid of agglomeration. These results support the viable use of carbon sphere particles in various engineering applications.

Atom Probe Tomography Analysis of TiCx Powders Synthesized by SHS in Al/Fe/Cu–Ti–C Systems

The stoichiometry of titanium carbide (TiCx) particles is important in determining particle properties. Spherical TiCx powders with particle sizes of 1–5 μm were produced by self-propagating high-temperature synthesis (SHS) in 30 wt.% Al–, 30 wt.% Cu–, and 30 wt.% Fe–Ti–C systems, respectively. To measure the compositions of the carbide powders, atom probe tomography (APT) tip specimens were carefully prepared by using a focus ion-beam milling method. APT analysis revealed that the TiCx particles formed in Al–, Cu–, and Fe–Ti–C systems are highly substoichiometric. The results are consistent with observations of the TiCx particles with a high content of oxygen and a certain amount of secondary metallic elements (Al, Cu, and Fe).

Metallic edge states in zig-zag vertically-oriented MoS2 nanowalls

The remarkable properties of layered materials such as MoS2 strongly depend on their dimensionality. Beyond manipulating their dimensions, it has been predicted that the electronic properties of MoS2 can also be tailored by carefully selecting the type of edge sites exposed. However, achieving full control over the type of exposed edge sites while simultaneously modifying the dimensionality of the nanostructures is highly challenging. Here we adopt a top-down approach based on focus ion beam in order to selectively pattern the exposed edge sites. This strategy allows us to select either the armchair (AC) or the zig-zag (ZZ) edges in the MoS2 nanostructures, as confirmed by high-resolution transmission electron microscopy measurements. The edge-type dependence of the local electronic properties in these MoS2 nanostructures is studied by means of electron energy-loss spectroscopy measurements. This way, we demonstrate that the ZZ-MoS2 nanostructures exhibit clear fingerprints of their predicted metallic character. Our results pave the way towards novel approaches for the design and fabrication of more complex nanostructures based on MoS2 and related layered materials for applications in fields such as electronics, optoelectronics, photovoltaics, and photocatalysts.