Electrical characterization is a critical step in the failure analysis workflow, a sequence that often ends in high-resolution imaging in the transmission electron microscope (TEM). Scanning TEM electron beam-induced current (STEM EBIC) is a technique that effectively combines these methods by performing electrical characterization at each imaging pixel, with the electron beam acting as a local current source. This work highlights the specimen preparation technique using the Ga FIB system followed by post-FIB Ar ion milling for STEM EBIC analysis. We present STEM EBIC as a technique to evaluate the surface quality of the specimens and to characterize the electronic properties of advanced devices at high resolution. With STEM EBIC, inactive and active finFET structures were clearly distinguished and improvements in sample quality from post-FIB Ar ion milling were evident.

The ability to precisely remove the internal structures of a semiconductor device, layer-by-layer, is a necessity for semiconductor research and failure analysis investigation. Currently, numerous techniques are used, such as mechanical polishing, chemical etching, and gas assisted plasma focused ion beam (FIB) milling. However, all of these techniques have limitations in that they are unable to: (1) delayer a millimeter-scale area with nanometer-scale uniformity, (2) rapidly remove thick (>300 nm) device layers, or (3) perform automatic and accurate end pointing, which is challenging on thin (≤300 nm) device layers.

Semiconductor devices are decreasing in dimensions and currently comprise stacks of ultrathin layers as in a spin-transfer torque magnetoresistive random-access memory (STTMRAM) device. For successful characterization by transmission electron microscopy (TEM) for failure analysis and device development, an accurate and controllable thinning of TEM specimens for is desirable. In this work, we combine plan view Ga focused ion beam (FIB) and post-FIB Ar milling preparation to prepare TEM specimens from a STT-MRAM device. Post-FIB Ar milling technique as a final polishing step of plan view TEM specimens was shown to prevent exposure of the tunnel barrier layer that can be damaged by the Ga FIB beam. We discuss the plan view FIB preparation, post-FIB Ar milling step and image analysis of the TEM images.

This paper describes an accurate and controllable delayering process to target defects in new materials and device structures. The workflow is a three-step process consisting of bulk device delayering by broad Ar ion beam milling, followed by plan view specimen preparation using a focused ion beam, then site-specific delayering via concentrated Ar ion beam milling. The end result is a precisely delayered device without sample preparation-induced artifacts suitable for identifying defects during physical failure analysis.

Fast and accurate examination from the bulk to the specific area of the defect in advanced semiconductor devices is critical in failure analysis. This work presents the use of Ar ion milling methods in combination with Ga focused ion beam (FIB) milling as a cutting-edge sample preparation technique from the bulk to specific areas by FIB lift-out without sample-preparation-induced artifacts. The result is an accurately delayered sample from which electron-transparent TEM specimens of less than 15 nm are obtained.

In this study, Fe-Cr-Al and Fe-Cr-Al-B cored wires were produced and deposited on steel substrates by wire arc spraying. The microstructure, hardness, and high-temperature corrosion behavior of the cored-wire deposits were evaluated in comparison to Fe-Cr and commercial Fe-Cr-Al solid-wire coatings. All coating samples exhibited lamellar microstructures with oxide inclusions, the fewest being in the Fe-Cr-Al-B deposits. Microhardness was measured along coating cross-sections at various distances from the coating-substrate interface. The Fe-Cr coatings were the hardest, followed by the Fe-Cr-Al-B deposits. Thermogravimetric analysis was used to evaluate high-temperature corrosion behavior in a molten salt environment under cyclic conditions, with the Fe-Cr-Al-B cored-wire deposits performing the best.

In this study, FeCrB coatings are deposited by wire arc spraying using powder cored wires to investigate the factors that affect thermal conductivity. Experimental results show that increasing boron content in the wires reduces oxide content in the coatings, which increases thermal conductivity. Annealing also increases thermal conductivity, which can be explained by grain growth and a reduction in porosity.

A series of Ni-based cored wires with different boron contents were designed to prepare corrosion-resistant coatings by two-roll wire-arc spraying. These coatings were evaluated for their potential to provide added protection and reduced maintenance for applications in waste-to-energy (WTE) plants. The as-deposited coatings, which primarily are composed of nanocrystalline particles, exhibit uniform and dense layered structures with porosity of about 3%. The investigators selected thermo-gravimetric techniques to evaluate the high-temperature corrosion behavior of the coatings in molten salt environment (Na 2 SO 4 -10 wt% NaCl) at 800°C. The coated surfaces exhibited significantly reduced corrosion rates in comparison to those of the SA 213-T 2 substrate during all tests. These results were due to the formation in the coatings of composite surface oxide films, including Cr 2 O 3 and NiCr 2 O 4 , which serve to prevent the diffusion or penetration of corrosive species. Furthermore, the boron content appears to have a significant influence on the corrosion behavior of the designed coatings: the coating with the best performance had 16 at. % B added. The wire-arc sprayed Ni-based coatings could be an effective and economical treatment to prevent corrosion and extend the lifetime of super-heater tubes in WTE plants.

A series of FeCrBCSi coatings were prepared by two-roll wire-arc spraying to investigate the influence of the boron content on the microstructure and properties of the coatings. Microstructural studies show that the as-deposited coatings present a dense layered structure with the porosity around 3%, and are primarily composed of a composite structure of amorphous phase and nanocrystalline phase. It is found that the addition of boron content within the composition range examined exhibits a significant effect on the phase component, as well as the microhardness and wear resistance of the coatings. The optimal composite phase structure, in terms of higher amorphous fraction and lesser nanocrystalline size distribution, leads to the relatively best performance of the coating with 26% boron added. The relative wear resistance of this coating is about 18 and 4 times higher than that of the Q235 steel and commercially available SHS 7170 coating, respectively, therefore wire-arc sprayed FeCrBCSi coating could be an effective and economic approach to withstand wear environment.