Ion-shadow method

It is time consuming and precise work to prepare a TEM cross-section sample by the ion milling method as described above. One has to glue the sample, grind the sample down to about 10 pm and then ion mill the sample at a low angle, 15°, to obtain electron transparency. In order to control the final ion milling process, one often has to check whether the sample is ready or not. Here we introduce a new simple and useful preparation method for TEM cross-section sample preparation the so-called ion shadow method [4.27]. 

The ion-shadow method was first introduced by Langer Katzer [4.28] and 

cut a thin-film sample into a strip of thickness 0.8 mm with a diamond cutter. Mechanically grind the sample down to less than 100 pm only from one side. Clean the sample with acetone and put the ground sample on a piece of glass, the ground surface facing the glass as shown in Fig. 4.15(a). Prepare a very thin diamond particle suspension by putting diamond powder (about 

2 pm to 1 pm in size, commercially available) into acetone or alcohol. Apply a small drop of the suspension on the glass a small distance away from the film 

Compared to the normal sample preparation method, this method takes much less time, and it is not necessary to check whether the sample is ready or not. By using this technique, one can obtain more or less the same quality cross-section samples as with the conventional method even for HREM studies. However, one can not tilt the sample so much. Fortunately, it is still suitable for an epitaxially grown thin film. 

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