Microwave Performance of 'Buffer-Free' GaN-on-SiC High Electron Mobility Transistors
Journal article, 2020

High performance microwave GaN-on-SiC HEMTs are demonstrated on a heterostructure without a conventional thick doped buffer. The HEMT is fabricated on a high-quality 0.25~\boldsymbol {\mu }\text{m} unintentional doped GaN layer grown directly on a transmorphic epitaxially grown AlN nucleation layer. This approach allows the AlN-nucleation layer to act as a back-barrier, limiting short channel effects and removing buffer leakage. The devices with the 'buffer-free' heterostructure show competitive DC and RF characteristics, as benchmarked against the devices made on a commercial Fe-doped epi-wafer. Peak transconductances of 500 mS/mm and a maximum saturated drain current of 1 A/mm are obtained. An extrinsic \text{f}-{\sf T} of 70 GHz and \text{f}-{\sf max} of 130 GHz are achieved for transistors with a gate length of 100 nm. Pulsed-IV measurements reveal a lower current slump and a smaller knee walkout. The dynamic IV performance translates to an output power of 4.1 W/mm, as measured with active load-pull at 3 GHz. These devices suggest that the 'buffer-free' concept may offer an alternative route for high frequency GaN HEMTs with less electron trapping effects.

microwave

buffer-free 23 heterostructure

GaN

HEMTs

Author

Ding Yuan Chen

SweGaN AB

Anna Malmros

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics, Microwave Electronics

Mattias Thorsell

SweGaN AB

Hans Hjelmgren

SweGaN AB

O. Kordina

SweGaN AB

J. T. Chen

SweGaN AB

Niklas Rorsman

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics, Microwave Electronics

IEEE Electron Device Letters

0741-3106 (ISSN)

Vol. 41 6 828-831 9068265

Ultrakompakt AESA-teknologi för autonoma flygfarkoster

VINNOVA, 2018-01-01 -- 2021-12-31.

Subject Categories

Condensed Matter Physics

DOI

10.1109/LED.2020.2988074

More information

Latest update

7/1/2020 1