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Microwave performance of ZnO/ZnMgO heterostructure field effect transistors
Author(s) -
Sasa Shigehiko,
Maitani Takeshi,
Furuya Yuto,
Amano Takeshi,
Koike Kazuto,
Yano Mitsuaki,
Inoue Masataka
Publication year - 2011
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.201000509
Subject(s) - materials science , transconductance , optoelectronics , cutoff frequency , microwave , heterojunction , molecular beam epitaxy , transistor , field effect transistor , substrate (aquarium) , sapphire , layer (electronics) , epitaxy , laser , electrical engineering , optics , nanotechnology , voltage , telecommunications , physics , computer science , oceanography , geology , engineering
We report the first microwave performance of single crystalline ZnO/ZnMgO heterostructure field‐effect transistors (HFETs). The structure consisted of a 15‐nm‐thick ZnO channel layer was grown by molecular beam epitaxy (MBE) on an a ‐sapphire substrate. Two‐finger type HFETs with 1 or 2‐µm‐long gate were fabricated and measured for microwave performance. The transconductance of the HFETs are 28 and 23 mS/mm for 1 and 2‐µm‐gate devices, respectively. The microwave measurement of ZnO‐based TFTs revealed that the current gain cutoff frequency f T of 1.75 GHz and that of unilateral power gain f max of 2.45 GHz for 1‐µm‐gate HFET. Electron velocity obtained by two‐terminal measurements implies that the structural design is crucial for further improvement of the high‐frequency performance of ZnO/ZnMgO HFETs.Small‐signal microwave characteristics of a 1‐µm‐gate ZnO/ZnMgO heterostructure FET. The current gain cutoff frequency of 1.75 GHz and the unilateral power gain cutoff frequency of 2.45 GHz were obtained.