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Subcritical barrier AlN/GaN E/D‐mode HFETs and inverters
Author(s) -
Zimmermann Tom,
Cao Yu,
Li Guowang,
Snider Gregory,
Jena Debdeep,
Xing Huili Grace
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.201001178
Subject(s) - heterojunction , materials science , optoelectronics , nitride , barrier layer , resistive touchscreen , noise margin , nanotechnology , layer (electronics) , voltage , transistor , electrical engineering , engineering
Enhancement‐ and depletion‐mode AlN/GaN HFETs have been fabricated with a subcritical barrier design: a two‐dimensional electron gas (2DEG) is induced in the highly resistive as‐grown heterostructure when a suitable capping material is deposited over the ultrathin AlN barrier. In this bottom‐up approach 2DEGs can be locally induced by patterned cap layers on subcritical barrier AlN/GaN heterostructures, which can enable the monolithic integration of enhancement‐ and depletion‐mode HFETs. An inverter circuit with 1.5 nm ultrathin AlN barrier E‐ and D‐mode HFETs was successfully demonstrated with reasonable voltage transfer characteristics, noise margin, and gain. To our best knowledge this is the first reported inverter based on subcritical barrier III–V nitride heterostructures.Integration of E‐ and D‐mode HFETs in a subcritical barrier AlN/GaN heterostructure, where n 2DEG ∼ 0 in the as‐grown structure. A patterned cap locally enhances 2DEG at the AlN/GaN hetero‐interface due to barrier lowering. It is an additive approach in contrast to the conventional gate recessing technique.