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.
A technique to cut out small pieces of samples directly from chips or wafer samples in a focused ion beam (FIB) system has been developed. A deep trench is FIB milled to cut out a small, wedge-shaped portion of the sample from the area of interest A micromanipulator with tungsten (W) probe is employed for lifting the micro-sample. The lifted micro-sample is then mounted on a carrier to prepare electron transparent thin foil specimens for transmission electron microscope (TEM) observation. We have also developed a method for site-specific TEM specimen preparation. In this method, FIB system and TEM/scanning transmission electron microscope (STEM) equipped with secondary electron (SE) detector are employed. An FIB–TEM/STEM compatible specimen holder has also been developed so that a specimen can be milled in the FIB system and observed in a TEM/STEM without remounting the specimen. STEM and scanning electron microscopy (SEM) images are used for locating a specific site on a specimen. SEM image observation at an accelerating voltage of 200kV enabled us to observe not only surface structures but also inner structures near the surface of a cross section with depth of field of around 1 micrometer. The STEM image allows the observation of inner structures of 3-5 micrometer thick specimens. Milling of a specimen by FIB and observation of the milled sample by SEM and STEM are alternately carried out until an electron transparent thin foil specimen is obtained. The position accuracy of the method in TEM specimen preparation is approximately 100nm.
The Perelomov coherent states of SU(1, 1) are labelled by elements of the quotient of SU(1, 1) by the compact subgroup. Taking advantage of the fact that this quotient is isomorphic to the affine group of the real line, we are able to parametrize the coherent states by elements of that group or equivalently by points in the half-plane. Such a formulation permits to find new properties of the SU(1, 1) coherent states and to relate them to affine wavelets.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.