In most cases sufficient sample quantity is available to cut the sample to fit the available window size of SIMS sample holders. However, in cases where only a small amount of material is available analysis of small (1 mm x 1 mm) samples is required. Some typical examples can be SiC specimens or decapsulated Si devices. The edge of a typical sample holder presents a large step, where the electric field lines are distorted and the primary/secondary beams alignment and measurement precision is dramatically affected. This edge effect becomes critical if the sample dimensions are comparable to the thickness of the sample window. For SIMS analyses, it is very important to have a flat surface in the analyzed and surrounding areas, therefore we have fabricated a special sample holder for very small specimens. A new mask has been designed and fabricated in which it is simple to analyze small sample sized and the precision of the sample holder has been tested showing good data repeatability. (C) 2004 Elsevier B.V. All rights reserved.