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High f T and f max AlGaN/GaN HFETs achieved by using thin and high‐Al‐composition AlGaN barrier layers and Cat‐CVD SiN passivation
Author(s) -
Higashiwaki M.,
Onojima N.,
Matsui T.,
Mimura T.
Publication year - 2006
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200565199
Subject(s) - materials science , chemical vapor deposition , passivation , heterojunction , optoelectronics , cutoff frequency , barrier layer , oscillation (cell signaling) , transistor , current density , layer (electronics) , nanotechnology , electrical engineering , chemistry , biochemistry , engineering , voltage , physics , quantum mechanics
We fabricated sub‐0.1 μm‐gate Al 0.4 Ga 0.6 N/GaN heterostructure field‐effect transistors (HFETs) with AlGaN barrier thicknesses of 4–10 nm. The devices were passivated with 2 nm‐thick SiN layers formed by catalytic chemical vapor deposition (Cat‐CVD). The Cat‐CVD SiN passivation greatly increased electron density, and the effect became more significant with decreasing AlGaN barrier thickness. The HFETs had maximum drain current densities of 1.1–1.5 A/mm and peak extrinsic transconductances of 305–438 mS/mm. Peak current‐gain cutoff frequency of 163 GHz and maximum oscillation frequency of 192 GHz were obtained for the devices with 8 nm‐thick AlGaN barriers. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)