f T and f rm MAX of 47 and 81 GHz , Respectively, on N-Polar GaN/AlN MIS-HEMT

In this letter, we demonstrate the record small-signal performance from N-polar GaN-based metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) by using a GaN spacer structure with an AlN barrier to reduce alloy scattering. High Si doping in GaN without excessive surface rough...

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Bibliographic Details
Published in:IEEE electron device letters 2009-01, Vol.30 (6)
Main Authors: Nidhi, Nidhi, Dasgupta, S, Pei, Yi, Swenson, B L, Brown, D F, Keller, S, Speck, J S, Mishra, U K
Format: Article
Language:English
Subjects:
Aluminum nitride
Contact resistance
Devices
Doping
Electron beam lithography
Gallium nitrides
Semiconductor devices
Spacers
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Summary:In this letter, we demonstrate the record small-signal performance from N-polar GaN-based metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) by using a GaN spacer structure with an AlN barrier to reduce alloy scattering. High Si doping in GaN without excessive surface roughening has been achieved using a digital doping scheme. A low ohmic contact resistance of 0.16 [iquest] . mm was measured. Submicrometer gates were fabricated by electron-beam lithography using a triple-layer resist process. f sub(T) and f sub(MAX) of 47 and 81 GHz, respectively, were obtained for the 150-nm-gate-length device. Further analysis has been done to understand the effect of access resistance on the high-frequency performance, defining a pathway for getting a higher gain and thus achieving a better high-frequency performance from N-polar GaN-based HEMTs.
ISSN:0741-3106
DOI:10.1109/LED.2009.2020305