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RF and DC characteristics in Al 2 O 3 /Si 3 N 4 insulated‐gate AlGaN/GaN heterostructure field‐effect transistors with regrown ohmic structure
Author(s) -
Maeda Narihiko,
Makimura Takashi,
Maruyama Takashi,
Wang Chengxin,
Hiroki Masanobu,
Yokoyama Haruki,
Makimoto Toshiki,
Kobayashi Takashi,
Enoki Takatomo
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.200565165
Subject(s) - transconductance , ohmic contact , materials science , cutoff frequency , optoelectronics , transistor , heterojunction , contact resistance , breakdown voltage , field effect transistor , leakage (economics) , voltage , electrical engineering , nanotechnology , layer (electronics) , economics , macroeconomics , engineering
Al 2 O 3 /Si 3 N 4 insulated‐gate AlGaN/GaN heterostructure field‐effect transistors (HFETs) have been fabricated, where the regrown ohmic structure was incorporated to reduce the contact resistance. Excellent DC and RF characteristics have been obtained together with the low gate leakage current as the result of employing the metal–insulator–semiconductor (MIS) structure. An HFET with a gate length ( L g ) of 0.1 μm has exhibited a drain current density ( I d ) and a transconductance ( g m ) of 1.30 A/mm and 293 mS/mm, respectively, with a reduced contact resistance of 0.3 Ω mm. The gate leakage current ( I g ) was as low as 1 × 10 –8 A/mm in the reverse vias region, and only 4 × 10 –5 A/mm even at a forward bias voltage of +3 V. In this device, the cutoff frequency ( f T ) and maximum oscillation frequency ( f max ) were estimated to be 70 and 90 GHz, respectively. In the HFETs with longer L g of 0.7 and 1.0 μm, f T and f max were 20 and 48 GHz ( L g = 0.7 μm), respectively; and 14 and 35 GHz ( L g = 1.0 μm), respectively. Thus, the Al 2 O 3 /Si 3 N 4 MIS HFETs have proved to also exhibit excellent RF characteristics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)