Tertiary electrons in single-event time-of-flight Rutherford backscattering spectrometry

Abstract

An effect of sample bias voltage on analysis time and time resolution of a single-event three-dimensional time-of-flight (ToF) Rutherford backscattering spectrometry (RBS) was evaluated with both experiment and simulation. Fluctuations of trajectories of secondary electrons were suppressed by positive sample bias voltage and most of the secondary electrons were collected by a secondary electron detector, resulting in short analysis-time and high time-resolution in the single-event three-dimensional ToF-RBS. On the contrary, negative sample bias voltage induced tertiary electrons at a focused ion beam (FIB) column by incident of the secondary electrons which accelerated by an electric field between the sample and the FIB column. The tertiary electrons improve analysis time, but deteriorate time resolution in the single-event three-dimensional ToF-RBS with negative sample bias voltage.