A New Focused Ion Beam Microsampling Technique for TEM Observation of Site-Specific Areas

Abstract

A new focused-ion-beam (FIB) micro(μ)-sampling technique has recently been developed to facilitate transmission electron microscope (TEM) specimen preparation, while allowing chips or wafer samples to remain intact. A deep trench is FIB-milled to dig out a small, wedge-shaped portion of the sample (or a microwedge) from the samples area of interest, leaving a small, brige-shaped portion (or a microbridge) to support the microwedge. A metal needle is then manipulated into position for lifting the microwedge, i.e., the μ-sample. FIB-assisted deposition (AD) is used to bond the needle to the μ-sample. FIB-milling of the microbridge then separates the μ-sample from the chip or wafer. The separated μ-sample is mounted onto a TEM grid and secured using FIB-AD. The μ-sample is then FIB-thinned further, to a strip of about 0.1 μm thick. All of the above steps are accomplished under vacuum in the FIB system. This design permits a reliable and user-friendly environment for TEM specimen preparation, while keeping chips or wafer samples intact. It also permits operators to repeat TEM inspection and FIB-milling so that precise areas of interest may be made available for TEM inspection. Both cross-sectional and plan view TEM μ-sampling are feasible.

Real-Space Observation of Short-Period Cubic Lattice of Skyrmions in MnGe

“…To overcome these difficulties we developed a following procedure (see Supplemental information for more details). First, the [001] oriented grains were selected from polycrystalline samples by an electron diffraction method using high-tilt angle TEM with wide gap (10 nm) objective lens, and then the selected [001]-oriented micro samples were picked out using a micro-manipulator in the focused ion beam (FIB) instruments (NB5000, Hitachi High-Technologies Co.) 42 . These micro samples were fixed onto a Mo support plate with the [001] direction normal to the plate and thinned down to 200 nm using FIB instrument.…”

High-Density, Large-Area Single-Walled Carbon Nanotube Networks on Nanoscale Patterned Substrates

“…Then, extra materials were removed from both sides of the region of interest using a focused Ga ion beam (FIB; Hitachi FB-2000A), until a very thin (electron microcopy transparent) specimen (200 nm) was obtained. Then, the thinning part was removed from the substrate and mounted on a copper grid using the “microsampling technique” 1 Schematic for designing high-density single-walled nanotube networks on patterned substrates using the CVD method: (a) preparation of submicrometer-scale patterned substrates (Si or SiO 2 ) by X-ray lithography; (b) thin catalyst (Fe or Co) film deposition on the 45°-tilted patterned substrate using a two-step process to cover the sides of the pillars; (c) schematic of nanotube networks bridging the pillars after CVD. …”

Three-Dimensional Observation of Magnetic Vortex Cores in Stacked Ferromagnetic Discs

“…Next, a carbon layer (300 nm) and a tungsten layer (500 nm) were deposited to protect the sample from Ga ion beam sputtering during the focused ion beam (FIB) process. A pillar sample containing two magnetic discs (Figure b) was prepared by using an FIB instrument (FB-2100, Hitachi High-Technologies Co.) equipped with a microsampling function . The method for preparing this sample is described elsewhere …”