Depth resolution studies in SiGe delta-doped multilayers using ultralow-energy Cs+ secondary ion mass spectrometry

Abstract

It is known that depth resolution can be improved by lowering the primary ion impact energy (Ep) and/or increasing the impact angle (θ) up to a critical θ, beyond which surface roughening ensues. However, lower Ep is accompanied by lower secondary ion yield, and for ultralow-energy Cs+ primary beam, a poorly focused beam. In this study, the authors subject a Ge delta-doped Si sample to ultralow-energy (