Specimen preparation for three-dimensional atom probe using the focused ion-beam lift-out technique

In three dimensional atom probe (3DAP) analysis, specimen preparation is of considerable significance. Specimens which are fabricated by the existing method are often ruptured from the part attaching the sample to the support needle because attachment force by deposition is not adequate. Specimen preparation methods which have stronger attachment force are required. In this study, we prepared some specimens using six types of cohesion methods in which the shape of contacting part between the sample and the support is different. We tested the strength of the specimens by applying the electric field to them, and searched the optimum specimen preparation method for 3DAP analysis using the results of comparison of physical strength and difficulty in fabrication of them. Then we concluded that specimen preparation method in which the sample was attached with the base needle by physical strengths of C-gas deposition in connected hole was the best way.