HR-(S)TEM Sample Preparation of Semiconducting Materials

High-resolution scanning transmission electron microscopy (HR-STEM) samples are mostlyprepared using Focused Ion Beam (FIB) milling. The aim of this work is to provide an alternativepreparation routes for semiconducting materials using mechanical and ion thinningtechniques. Samples of silicon, silicon germanium and gallium nitride are prepared. A generalroute is applied to understand the materials, and an alternative route (using the MultiPrep™Polishing System from Allied High Tech) has been implemented based on the type and thecharacteristics of the sample material. Filtered and unfiltered bright field images are recordedfrom each sample, and t/λ graphs are extracted. These graphs provide an estimate of thesample thickness in relation to the mean-free path using the Log-Ratio-Method [1]. Based onthe recorded t/λ maps, a conclusion and an optimal preparation route is recommended foreach material prepared.