Influence of material properties on TEM specimen preparation of thin films

Several factors must be taken into account when deciding which specimen preparation technique(s) to use. These factors include the amount of material available, ease of preparing this material due to its properties and familiarity, location and size of the region of interest, amount of information sought, facilities accessible, and time available by the researcher to devote to the preparation of the specimen. The more popular specimen preparations for thin films, namely, electropolishing, cleaving, crushing, mechanical thinning followed by ion milling, and ultramicrotomy are discussed and the more unusual techniques such as extraction/replication, photochemical etching, lithography and reactive ion etching (RIE), chemically assisted ion beam etching (CAIBE), and precision polishing-based techniques are described. Their advantages and disadvantages in the context of the above factors are discussed. Suggestions for increasing one's success rate in preparing specimens are given. The role of transmission electron microscopy (TEM) analysis is considered since it rarely stands in isolation from other physical analytical techniques, nor is it often used as a quick diagnostic tool. Conservation of material by the minimization of the amount of material used (or destroyed) by TEM specimen preparation, and conservation of one's time by performing TEM analysis only on "worthy" samples should be given maximum consideration.