Diamond lateral FinFET with triode-like behavior

Biqin Huang,Xiwei Bai,Samuel J Kim,Stephen K Lam

doi:10.1038/s41598-020-59049-5

Biqin Huang, Xiwei Bai + Show 2 more

Open Access

https://doi.org/10.1038/s41598-020-59049-5

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Journal: Scientific Reports	Publication Date: Feb 10, 2020
Citations: 5	License type: open-access

Affiliation: HRL Laboratories (United States)

Abstract

In this letter we report a diamond lateral FinFET fabricated using an ohmic regrowth technique. The use of ohmic regrowth separates the source/drain and gate fabrication, providing a viable means to improve ohmic contact resistance while protecting the top surface of the diamond channel from dry etch damage. Enabled by high channel quality, the diamond transistor behavior was shown to transit from a pentode-like to a triode-like characteristic when channel length decreased. For the first time, space charge limited transport in diamond FinFETs with a short channel length was demonstrated. We have analyzed the space charge limited transport from room temperature to 150 °C. This space charge limited transport, in combination with improved ohmic contacts, will enable diamond FinFETs for various high-power applications.

Highlights

In this letter we report a diamond lateral FinFET fabricated using an ohmic regrowth technique
Most studies have been focused on hydrogen-terminated FETs (HFETs) due to the ease of creating a p type conductive channel in diamond by hydrogen surface termination[1]
We demonstrated diamond FinFET devices with different transistor behaviors that benefited from the improved fin channel and ohmic contact

Summary

Introduction

In this letter we report a diamond lateral FinFET fabricated using an ohmic regrowth technique. Significant progress has been made in HFET, there are concerns regarding the long-term stability of two-dimensional hole gas and the low mobility[2] at high carrier concentration To overcome these limitations, we recently demonstrated a new device, diamond FinFET3, by leveraging the latest device concept in the silicon CMOS industry. The plasma- based etch process inevitably damages the top surface of the fin channel, leading to potentially high surface defects and low channel mobility To avoid these issues, we adopted a widely used ohmic regrowth technology[4] for diamond FinFET. Once this pinch-off point reaches the source, the device current starts to increase, eventually leading to a regime in which space charge limited transport dominates In this regime, the device behaves like a vacuum triode, where current is proportional to the square power of voltage bias[5].

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