Atom probe tomography of high-performance Si solar cells. Towards the visualization of Si heterojunctions and nanocrystallites via hydrogen detection

Atom probe tomography (APT) is a method for obtaining three-dimensional (3D) distributions of elements in materials with nearly atomic-scale resolution. While APT has attracted considerable attention as a promising 3D analysis for various materials and their device structures owing to upgrading the APT system in terms of hardware and software, successful data acquisition relies substantially on a desired preparation of needle-shaped specimens. In this article, technical advances for near-surface analysis on textured (non-flat) samples using a site-specific lift-out method processed with a focused ion beam are provided. As an application of research with APT, the author reviews a trial of the quantification of hydrogen in hydrogenated amorphous Si (a-Si:H) in high-performance Si solar cells and 3D mapping of nanocrystallites embedded in a-Si:H via hydrogen depletion. (author)