Kelvin probe characterization of buried graphitic microchannels in single-crystal diamond

TL;DR

This paper demonstrates the use of Kelvin Probe Microscopy to non-invasively characterize buried graphitic microchannels in single-crystal diamond, revealing electrical properties and conduction behavior with micrometer resolution.

Contribution

It introduces a novel application of KPM for detailed electronic characterization of buried conductive channels in diamond, enabling non-invasive resistivity measurements.

Findings

KPM maps clearly visualize buried channels under electrical bias.

Opposite contrast regions indicate different conduction properties.

The method offers a powerful diagnostic tool for diamond-based electronic devices.

Abstract

In this work, we present an investigation by Kelvin Probe Microscopy (KPM) of buried graphitic microchannels fabricated in single-crystal diamond by direct MeV ion microbeam writing. Metal deposition of variable-thickness masks was adopted to implant channels with emerging endpoints and high temperature annealing was performed in order to induce the graphitization of the highly-damaged buried region. When an electrical current was flowing through the biased buried channel, the structure was clearly evidenced by KPM maps of the electrical potential of the surface region overlying the channel at increasing distances from the grounded electrode. The KPM profiling shows regions of opposite contrast located at different distances from the endpoints of the channel. This effect is attributed to the different electrical conduction properties of the surface and of the buried graphitic layer. The model adopted to interpret these KPM maps and profiles proved to be suitable for the electronic characterization of buried conductive channels, providing a non-invasive method to measure the local resistivity with a micrometer resolution. The results demonstrate the potential of the technique as a powerful diagnostic tool to monitor the functionality of all-carbon graphite/diamond devices to be fabricated by MeV ion beam lithography.