Direct observation of hydrogen at defects in multicrystalline silicon

Abstract

Hydrogen passivation is a key industrial technique used to reduce the recombination activity of defects in multicrystalline silicon (mc-Si). However, not all dislocations and grain boundaries respond well to traditional hydrogen passivation techniques. In order to understand the reasons for these different behaviours, and how superior passivation might be achieved, a method is required for the direct observation of hydrogen at these defects. Here, we present a novel characterisation technique based on a combination of transmission Kikuchi diffraction (TKD), atom probe tomography (APT), and isotopic substitution that enables unambiguous detection and quantification of hydrogen atoms present at crystallographic defects in mc-Si.