Some aspects of the field evaporation behaviour of GaSb

TL;DR

This study investigates the complex field evaporation behavior of GaSb in atom probe tomography, highlighting variations in charge states and ion clustering influenced by electric fields, and compares it with metallic materials.

Contribution

It provides a detailed analysis of GaSb evaporation behavior and proposes that spatial correlation and ion dissociation cause measurement inaccuracies.

Findings

GaSb shows strong variations in charge states and ion clustering.

Evaporation behavior differs significantly from metallic materials.

Field-induced dissociation affects composition accuracy.

Abstract

In-depth analysis of pulsed laser atom probe tomography (APT) data on the field evaporation of the III V semiconductor material GaSb reveals strong variations in charge states, relative abundances of different cluster ions, multiplicity of detector events and spatial correlation of evaporation events, as a function of the effective electric field at the specimen surface. These variations are discussed in comparison with the behaviour of two different metallic specimen materials, an Al-6XXX series alloy and pure W, studied under closely related experimental conditions in the same atom probe instrument. It is proposed that the complex behaviour of GaSb originates from a combination of spatially correlated evaporation events and the subsequent field induced dissociation of cluster ions, the latter contributing to inaccuracies in the overall atom probe composition determination for this material.