Diamond Field-Effect Transistors With V2O5-Induced Transfer Doping: Scaling to 50-nm Gate Length

Kevin G Crawford,A Glen Birdwell,Khamsouk Kingkeo,James D Weil,Dmitry A Ruzmetov,Tony G Ivanov,Mahesh R Neupane,Pankaj B Shah

doi:10.1109/ted.2020.2989736

Kevin G Crawford, A Glen Birdwell + Show 6 more

Open Access

https://doi.org/10.1109/ted.2020.2989736

Copy DOI

Abstract

Wereport on the fabrication and measurement of hydrogen-terminated diamond field-effect transistors (FETs) incorporating V2O5 as a surface acceptor material to induce transfer doping. Comparing a range of gate lengths down to 50 nm, we observe inversely scaling peak output current and transconductance. Devices exhibited a peak drain current of ~700 mA/mm and a peak transconductance of ~150 mS/mm, some of the highest reported thus far for a diamond metal semiconductor FET (MESFET). Reduced sheet resistance of the diamond surface after V2O5 deposition was verified by four probe measurement. These results show great potential for improvement of diamond FET devices through scaling of critical dimensions and adoption of robust transition metal oxides such as V2O5.

Highlights

I NTEREST in the diamond material system for electronic applications has rapidly increased in recent years, becoming a global scale area of interest
A clear trend between reduced gate length and increased current (Id )/transconductance is observed, with small dispersion between data points indicating good yield across the substrate relative to what is typically observed on hydrogen-terminated diamond
Four probe measurement of a van der Pauw (VDP) structure on the substrate showed a reduction in sheet resistance from 14.2 to 6.8 k/ after deposition of V2O5, a decrease consistent with other such reported results [11], [12]

Summary

INTRODUCTION

I NTEREST in the diamond material system for electronic applications has rapidly increased in recent years, becoming a global scale area of interest. When in intimate contact with the hydrogen-terminated diamond surface, these high electron affinity materials will prompt the transfer of electrons from the diamond, acting as an electron accepter. This process leaves behind corresponding holes within the diamond, forming a 2-D hole gas (2DHG) beneath the surface [8], [10], [11]. This approach of encapsulation with a transition metal oxide has been incorporated into our diamond metal semiconductor FET (MESFET) designs, improving output current density and stability of devices. By reducing gate length (Lg), peak output current and transconductance are improved significantly

EXPERIMENTAL

RESULTS

CONCLUSION