Electrostatic Landscape of a H-Silicon Surface Probed by a Moveable Quantum Dot

TL;DR

This study maps the electrostatic potential of a hydrogen-terminated silicon surface at the atomic scale, revealing how charged species influence local fields, which is crucial for nanoelectronic device stability and performance.

Contribution

It introduces a method to characterize atomic-scale electrostatic landscapes and identifies the nature of near-surface charged species using a moveable quantum dot probe.

Findings

Charged species significantly affect local electrostatic potential.

Identified the near-surface species as likely a negatively charged hydrogen vacancy or interstitial hydrogen.

Demonstrated the use of a moveable quantum dot for atomic-scale electrostatic mapping.

Abstract

With nanoelectronics reaching the limit of atom-sized devices, it has become critical to examine how irregularities in the local environment can affect device functionality. Here, we characterize the influence of charged atomic species on the electrostatic potential of a semiconductor surface at the sub-nanometer scale. Using non-contact atomic force microscopy, two-dimensional maps of the contact potential difference are used to show the spatially varying electrostatic potential on the (100) surface of hydrogen-terminated highly-doped silicon. Three types of charged species, one on the surface and two within the bulk, are examined. An electric field sensitive spectroscopic signature of a single probe atom reports on nearby charged species. The identity of one of the near-surface species has been uncertain. That species, suspected of being boron or perhaps a negatively charged donor species, we suggest is of a character more consistent with either a negatively charged interstitial hydrogen or a hydrogen vacancy complex.