Characterization of the Noise in Secondary Ion Mass Spectrometry Depth Profiles

TL;DR

This study investigates the noise characteristics in SIMS depth profiles, revealing that the noise follows a Poisson distribution and analyzing detector saturation effects.

Contribution

It provides a detailed characterization of SIMS noise, demonstrating Poissonian behavior and analyzing detector saturation and hysteresis effects.

Findings

Noise in SIMS depth profiles follows a Poisson distribution.

Poissonian relation accurately describes mean-square error and mean.

Detector saturation causes deviations and hysteresis in measurements.

Abstract

The noise in the depth profiles of secondary ion mass spectrometry (SIMS) is studied using different samples under various experimental conditions. Despite the noise contributions from various parts of the dynamic SIMS process, its overall character agrees very well with the Poissonian rather than the Gaussian distribution in all circumstances. The Poissonian relation between the measured mean-square error (MSE) and mean can be used to describe our data in the range of four orders. The departure from this relation at high counts is analyzed and found to be due to the saturation of the channeltron used. Once saturated, the detector was found to exhibit hysteresis between rising and falling input flux and output counts.