Dealing with image shifting in 3D ToF-SIMS depth profiles

The high sputter efficiency and low damage of gas cluster ion beams have enabled depth profiling to greater depths within organic samples using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Due to the typically fixed geometry of the ion sources used in ToF-SIMS, as one digs into a surface, the position sampled by ion beams shifts laterally. This causes a lateral shift in the resulting images that can become quite significant when profiling down more than one micron. Here, three methods to compensate for this image shifting are presented in order to more accurately stack the images to present a 3D representation. These methods include (1) using software to correct the image shifts post-acquisition, (2) correcting the sample height during acquisition, and (3) adjusting the beam position during acquisition. The advantages and disadvantages of these methods are discussed. It was found that all three methods were successful in compensating for image shifting in ToF-SIMS depth profiles resulting in...