Charge Crowding in Graphene-Silicon Diodes

TL;DR

This paper investigates charge transport and failure mechanisms at graphene-silicon ohmic contacts, revealing how charge crowding affects device reliability and proposing strategies to improve robustness in 2D-3D heterostructures.

Contribution

It introduces a detailed analysis of charge crowding effects in graphene-silicon diodes and demonstrates methods to mitigate device failure under high electrical stress.

Findings

Severe current crowding impacts device failure.

Spatial variation in contact properties reduces failure.

Devices show high robustness against electrostatic discharges.

Abstract

The performance of nanoscale electronic devices based on a two-three dimensional (2D-3D) interface is significantly affected by the electrical contacts that interconnect these materials with external circuitry. This work investigates charge transport effects at the 2D-3D ohmic contact coupled with the thermionic injection model for graphene/Si Schottky junction. Here, w e focus on the intrinsic properties of graphene-metal contacts, paying particular attention to the nature of the contact failure mechanism under high electrical stress. According to our findings, severe current crowding (CC) effects in highly conductive electrical contact significantly affect device failure that can be reduced by spatially varying the contact properties and geometry. The impact of electrical breakdown on material degradation is systematically analyzed by atomic force, Raman, scanning electron, and energy dispersive X-ray spectroscopies. Our devices withstand high electrostatic discharge spikes over a longer period, manifesting high robustness and operational stability. This research paves the way towards a highly robust and reliable graphene/Si heterostructure in futuristic on-chip integration in dynamic switching. The methods we employed here can be extended for other nanoscale electronic devices based on 2D-3D interfaces