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Impact of gate dielectric thickness on the electrical properties of AlGaN/GaN MISHFETs on Si(111) substrate
Author(s) -
Eickelkamp Martin,
Fahle Dirk,
Lindner Johannes,
Heuken Michael,
Lautensack Christian,
Kalisch Holger,
Jansen Rolf H.,
Vescan Andrei
Publication year - 2010
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.200983554
Subject(s) - materials science , optoelectronics , passivation , dielectric , gate dielectric , atomic layer deposition , fabrication , heterojunction , gate oxide , transistor , substrate (aquarium) , leakage (economics) , oxide , layer (electronics) , electrical engineering , composite material , voltage , medicine , oceanography , alternative medicine , pathology , geology , metallurgy , economics , macroeconomics , engineering
We report on the fabrication and characterization of AlGaN/GaN metal–insulator–semiconductor heterostructure field effect transistors (MISHFETs) using HfO 2 and Al 2 O 3 as gate dielectric, deposited by atomic layer deposition (ALD). Improved device performance has been observed for all MISHFET devices as compared to the reference HFET. The additional dielectric layer underneath the gate metallization leads to a significant decrease of gate leakage currents and thus prevents device degradation and losses. Furthermore, the 2DEG sheet carrier concentration increases depending on the k ‐value of the oxide as well as the oxide thickness. The thin (3–9 nm) dielectric layer is serving simultaneously as surface passivation, mitigating dc‐to‐rf dispersion. However, less has been reported about the impact of gate insulator thickness on the electrical performance, in particular in terms of dc‐to‐rf dispersion. In this paper, full recovery of dc drain current is demonstrated with a MISHFET with 9 nm Al 2 O 3 oxide thickness.