Metallic Nanoneedles Arrays for TEM Sample Preparation 'Lift-Out'

摘要

The sample preparation for transmission electron microscope (TEM) can be done using a method known as "Lift-out". [1-2] In this process a sharp tungsten probe is welded using a focused ion beam (FIB) to the sample in order to transfer it to the TEM sample holder where it is released from the tungsten tip. There are a few problems: the sharpening process of the tungsten probe is time consuming, and the tungsten probe must be replaced after a few times use. Also, the extended sharpened probe is always in parallel with the tungsten probe, which limits the application. Here, we have demonstrated a method of using a Ag_2Ga nanoneedle array for a quicker sharpening process of tungsten probes with a better sample viewing. For that, a nanoneedle array substrate is kept in the FIB system and each nanoneedle is welded (with any desired angle) to the tungsten probe. It is then detached from the array base and used as a sharp, flexible tip for lift-out of the TEM samples. The experimental details are explained in the following.