Etching of Graphene Devices with a Helium Ion Beam

TL;DR

This paper explores helium ion beam etching of graphene devices, demonstrating nanostructuring and electrical isolation capabilities, with insights into process parameters and residual conductivity effects.

Contribution

It introduces a method for precise helium ion beam etching of graphene, including in situ electrical measurements, and analyzes effects on different substrates and residual conductivity.

Findings

Successful etching of graphene with ~10 nm gaps

Lower ion doses needed for SiO2-supported graphene

Residual conductivity linked to hydrocarbon contamination

Abstract

We report on the etching of graphene devices with a helium ion beam, including in situ electrical measurement during lithography. The etching process can be used to nanostructure and electrically isolate different regions in a graphene device, as demonstrated by etching a channel in a suspended graphene device with etched gaps down to about 10 nm. Graphene devices on silicon dioxide (SiO2) substrates etch with lower He ion doses and are found to have a residual conductivity after etching, which we attribute to contamination by hydrocarbons.