Single-Electron Capacitance Spectroscopy of Individual Dopants in Silicon

TL;DR

This paper demonstrates a capacitance-based scanning probe technique to detect and analyze individual subsurface dopants in silicon, revealing their quantum states and interactions at the atomic scale.

Contribution

It introduces a novel method for spatially resolving and spectroscopically studying single dopants deep below silicon surfaces.

Findings

Successfully detected individual subsurface boron acceptors.

Observed energy shifts of the B+ state related to dopant interactions.

Provided insights into dopant-dopant interactions at the atomic level.

Abstract

Motivated by recent transport experiments and proposed atomic-scale semiconductor devices, we present measurements that extend the reach of scanned-probe methods to discern the properties of individual dopants tens of nanometers below the surface of a silicon sample. Using a capacitance-based approach, we have both spatially-resolved individual subsurface boron acceptors and detected spectroscopically single holes entering and leaving these minute systems of atoms. A resonance identified as the B+ state is shown to shift in energy from acceptor to acceptor. We examine this behavior with respect to nearest-neighbor distances. By directly measuring the quantum levels and testing the effect of dopant-dopant interactions, this method represents a valuable tool for the development of future atomic-scale semiconductor devices.