A FIB Micro-Sampling Technique and a Site-Specific TEM Specimen Preparation Method for Precision Materials Characterization

Abstract

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.

Strain-Driven Growth of Zinc Oxide Nanowires on Sapphire: Transition from Horizontal to Standing Growth

“…Using a FEI DualBeam instrument, a combination of a focused Ga ion beam and a scanning electron microscope (SEM), electron-transparent cross sections of horizontally grown NWs on a -plane sapphire were prepared. This technique, which is often called FIB-assisted membrane lift-out, is the best available method in terms of resolution and site specificity for preparing TEM specimens. , In this study, the procedure for making the membranes was adapted from that described in ref . The cross sections of horizontal NWs were characterized using a FEI-Philips CM 300 TEM with a 300 kV accelerating voltage.…”

“…This technique, which is often called FIB-assisted membrane liftout, is the best available method in terms of resolution and site specificity for preparing TEM specimens. 17,18 In this study, the procedure for making the membranes was adapted from that described in ref 19. The cross sections of horizontal NWs were characterized using a FEI-Philips CM 300 TEM with a 300 kV accelerating voltage.…”

Multiple Double Cross-Section Transmission Electron Microscope Sample Preparation of Specific Sub-10 nm Diameter Si Nanowire Devices

“…An in situ lift-out (ISLO) (Yaguchi et al, 2001; Mayer et al, 2007) XTEM1 sample was prepared of the Si NW ROI using an FEI Co. (Hillsboro, OR, USA) model Helios 400s DB-FIB with Pt GIS and an Omniprobe (Dallas, TX, USA) model 250 micromanipulator. In this system, the electron column is mounted vertically, and the FIB Ga + ion column is mounted 52° from the electron column.…”

Sample Preparation Techniques for Transmission Electron Microscopy

“…Three fundamental FIB techniques to prepare TEM lamellae are (i) the H-bar or trench method [63], (ii) the in situ lift-out method [64], and (iii) the ex situ lift-out method [65]. Before cutting, a metal or a carbon layer should be deposited on the area of interest to protect the surface during the specimen milling process.…”