Microscopy and Microanalysis

Techniques and Software Development

Improved Focused Ion Beam Target Preparation of (S)TEM Specimen—A Method for Obtaining Ultrathin Lamellae

Lorenz Lechnera1 p1 c1, Johannes Biskupeka1 and Ute Kaisera1

a1 Center for Electron Microscopy, Materials Science Group, Ulm University, Ulm, Germany

Abstract

Specimen quality is vital to (scanning) transmission electron microscopy (TEM) investigations. In particular, thin specimens are required to obtain excellent high-resolution TEM images. Conventional focused ion beam (FIB) preparation methods cannot be employed to reliably create high quality specimens much thinner than 20 nm. We have developed a method for in situ target preparation of ultrathin TEM lamellae by FIB milling. With this method we are able to routinely obtain large area lamellae with coplanar faces, thinner than 10 nm. The resulting specimens are suitable for low kV TEM as well as scanning TEM. We have demonstrated atomic resolution by Cs-corrected high-resolution TEM at 20 kV on a FIB milled Si specimen only 4 nm thick; its amorphous layer measuring less than 1 nm in total.

(Received July 05 2011)

(Accepted September 23 2011)

Correspondence:

c1 Corresponding author. E-mail: lechner@nts.zeiss.com

p1 Current affiliation: Carl Zeiss Microscopy, Carl-Zeiss-Straße 56, 73447 Oberkochen, Germany