Speaker
Description
A major challenge with cryogenic atom probe sample preparation is that Gas Injection System based deposition is generally unsuitable to liftout and mount samples to support structures due to a lack of control of deposition. Developments in localized in-situ sputtering of metals have avoided this issue and have facilitated mounting of samples for many material systems requiring cryogenic conditions, including free standing liquids. This approach requires an initial amount of redeposition from the sample to the support structure itself prior to any in-situ redeposition from the sputter source and so relies on a significant amount of contact between the sample and support structure. In the case of sample liftouts with non typical geometries such as those involving free standing thin films or materials that mill very easily compared to the support structure, this can prove extremely difficult as no firm contact can be made and the sample is frequently lost. This is especially an issue when using plasma based species for milling due to the decreased resolution of the beam. In these situations, a a more reliable method to carry that initial attachment is required.
In this presentation, we demonstrate a method of lifting out and mounting atom probe samples at cryogenic conditions using a commercially available vacuum safe and electron curing liquid adhesive called “Sem-Glu” (Kleindiek). This adhesive remains viscous to -90°C and so can be applied in-situ via the micromanipulator down to this temperature if the material system is stable at these temperatures but will promote still adhesion to a surface and can be used down to -180°C if applied in advance at room temperature to manipulators and supports structures.
