Focused Ion Beam Microscopy

There are several processes that limit the image quality of focused ion beam microscopy. In a fixed dwell time, randomness in the source ion beam results in a random number of ions incident on the sample (we call this source shot noise). Each incident ion causes a random number of secondary electrons to be dislodged from the sample. In addition, the detection of the dislodged secondary electrons is also a further source of noise.

Our work focuses on developing an understanding of (and models for) these phenomena along with estimation algorithms, that push the limits beyond what is presently achievable.

Conventionally, increasing ion dose will improve the image quality but also causes more damage to the sample, we aim to make the most of a fixed dose. As shown in [1, 2], time-resolved sensing can enable dose reduction for any desired image quality, in return minimize damage caused to sample of interest. In further exploration, we plan to extend the method to more estimates for the image to infer the topography of the sample.

Selected publications

1. M. Peng, J. Murray-Bruce, K. K. Berggren and V. K. Goyal, Source Shot Noise Mitigation in Helium Ion and Focused Ion Beam Microscopy. In Proc. Int. Conf. on Helium and emerging Focused Ion Beams, Dresden, Germany, June 2018.
2. M. Peng, J. Murray-Bruce, K. K. Berggren and V. K. Goyal, Source Shot Noise Mitigation in Scanned Beam Microscopy. In Proc. Int. Conf. on Electron, Ion, and Photon Beam Technology and Nanofabrication, Puerto Rico, May 2018.