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Saturation Velocity Measurement of Al0.7Ga0.3N-Channel High Electron Mobility Transistors

Journal of Electronic Materials

Klein, Brianna A.; Baca, A.G.; Lepkowski, Stefan M.; Nordquist, Christopher N.; Wendt, J.R.; Allerman, A.A.; Armstrong, Andrew A.; Douglas, Erica A.; Abate, Vincent M.; Kaplar, Robert K.

Gate length dependent (80 nm–5000 mm) radio frequency measurements to extract saturation velocity are reported for Al0.85Ga0.15N/Al0.7Ga0.3N high electron mobility transistors fabricated into radio frequency devices using electron beam lithography. Direct current characterization revealed the threshold voltage shifting positively with increasing gate length, with devices changing from depletion mode to enhancement mode when the gate length was greater than or equal to 450 nm. Transconductance varied from 10 mS/mm to 25 mS/mm, with the 450 nm device having the highest values. Maximum drain current density was 268 mA/mm at 10 V gate bias. Scattering-parameter characterization revealed a maximum unity gain bandwidth (fT) of 28 GHz, achieved by the 80 nm gate length device. A saturation velocity value of 3.8 × 106 cm/s, or 35% of the maximum saturation velocity reported for GaN, was extracted from the fT measurements.

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TYPE Journal Article YEAR 2019
DOIOSTIScopus

IRPS Increases its Coverage of SiC and GaN

Compound Semiconductor

Kaplar, Robert K.; Meneghini, Matteo; Lelis, Aivars

Over the past few years, interest has rocketed in the use of wide bandgap devices for energy-efficiency applications such as the electric grid, vehicle electrification, and more-electric aircraft. Deployed in these situations, devices must have a high reliability. In fact, this attribute is so crucial that it is a primary gatingfactor, determining the rate at which these wide bandgap devices are being inserted into these system applications.

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TYPE Journal Article YEAR 2019
OSTI

ITRW: Formulating a Roadmap for WBG and UWBG Materials and Devices

Veliadis, Victor; Kaplar, Robert K.; Zhang, Jon; Khalil, Sameh; Flicker, Jack D.; Neely, Jason C.; Binder, Andrew B.; Atcitty, Stanley A.; Moens, Peter; Bakowski, Mietek; Hollis, Mark

The purpose of the International Technology Roadmap for Wide-Bandgap Power Semiconductors (ITRW) Materials and Devices Working Group, which considers the materials science of Wide-and Ultra-Wide-Band-Gap (WBG and UWBG) semiconductors, in addition to device design, fabrication, and evaluation, is to formulate a long-term, international roadmap for WBG and UWBG materials and devices, consistent with the packaging and applications working groups of ITRW. The working group is co-chaired by Victor Veliadis (primarily representing silicon carbide (SiC) and related materials) and Robert Kaplar (primarily representing gallium nitride (GaN) and related materials, as well as emerging ultra-WBGs) and is split into four sub-working-groups, which are: 1) SiC materials and devices (co-chairs Jon Zhang and Mietek Bakowski). 2) Lateral GaN materials and devices (co-chairs Sameh Khalil and Peter Moens). 3) Vertical GaN materials and devices (co-chairs TBD). 4) Emerging UWBG materials and devices (co-chairs Mark Hollis). The first two subgroups represent technology that is far more mature than that of the latter two, and devices are available as commercial products in power applications. The primary focus of this article will be on developments in subgroups 1 and 2, with only brief descriptions of the latter two sub-groups, including future activities as they mature technologically.

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TYPE Other Report YEAR 2019
DOIOSTI

RF Performance of Al0.85Ga0.15N/Al0.70Ga0.30N high electron mobility transistors with 80-nm Gates

IEEE Electron Device Letters

Baca, A.G.; Klein, Brianna A.; Wendt, J.R.; Lepkowski, Stefan M.; Nordquist, Christopher N.; Armstrong, Andrew A.; Allerman, A.A.; Douglas, Erica A.; Kaplar, Robert K.

Al-rich AlGaN-channel high electron mobility transistors with 80-nm long gates and 85% (70%) Al in the barrier (channel) were evaluated for RF performance. The dc characteristics include a maximum current of 160 mA/mm with a transconductance of 24 mS/mm, limited by source and drain contacts, and an on/off current ratio of 109. fT of 28.4 GHz and fMAX of 18.5 GHz were determined from small-signal S-parameter measurements. Output power density of 0.38 W/mm was realized at 3 GHz in a power sweep using on-wafer load pull techniques.

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TYPE Journal Article YEAR 2019
DOIOSTIScopus

III-Nitride ultra-wide-bandgap electronic devices

Semiconductors and Semimetals

Kaplar, Robert K.; Allerman, A.A.; Armstrong, Andrew A.; Baca, A.G.; Crawford, Mary H.; Dickerson, Jeramy R.; Douglas, Erica A.; Fischer, Arthur D.; Klein, Brianna A.; Reza, Shahed R.

This chapter discusses the motivation for the use of Ultra-Wide-Bandgap Aluminum Gallium Nitride semiconductors for power switching and radio-frequency applications. A review of the relevant figures of merit for both vertical and lateral power switching devices, as well as lateral radio-frequency devices, is presented, demonstrating the potential superior performance of these devices relative to Gallium Nitride. Additionally, representative results from the literature for each device type are reviewed, highlighting recent progress as well as areas for further research.

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TYPE Book YEAR 2019
OSTIScopus
Results 101–125 of 332
Results 101–125 of 332