Mapping the potential within a nanoscale undoped GaAs region using a scanning electron microscope

TL;DR

This paper demonstrates a method to map the electric potential within nanoscale undoped GaAs regions using secondary electron imaging in a SEM, providing direct visualization of electrostatic potential variations.

Contribution

It introduces a novel application of SEM secondary electron imaging to directly map electrostatic potential in undoped semiconductor regions, expanding the capabilities of dopant profiling techniques.

Findings

Potential mapping of a 90nm undoped GaAs channel was successfully achieved.

Secondary electron emission intensities correlated with numerical electric potential solutions.

The method enables direct observation of electrostatic variations in undoped semiconductor regions.

Abstract

Semiconductor dopant profiling using secondary electron imaging in a scanning electron microscope (SEM) has been developed in recent years. In this paper, we show that the mechanism behind it also allows mapping of the electric potential of undoped regions. By using an unbiased GaAs/AlGaAs heterostructure, this article demonstrates the direct observation of the electrostatic potential variation inside a 90nm wide undoped GaAs channel surrounded by ionized dopants. The secondary electron emission intensities are compared with two-dimensional numerical solutions of the electric potential.