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Effect of Sputter Deposition Atmosphere of AlN on the Electrical Properties of Hydrogen‐Terminated Diamond Field Effect Transistor with AlN/Al 2 O 3 Stack Gate
Author(s) -
Banal Ryan G.,
Imura Masataka,
Ohata Hirohito,
Liao Meiyong,
Liu Jiangwei,
Koide Yasuo
Publication year - 2017
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.201700463
Subject(s) - misfet , materials science , optoelectronics , diamond , atomic layer deposition , gate dielectric , sputtering , threshold voltage , field effect transistor , analytical chemistry (journal) , transistor , layer (electronics) , voltage , thin film , nanotechnology , electrical engineering , chemistry , metallurgy , chromatography , engineering
The electrical properties of hydrogen‐terminated diamond (H‐diamond) metal–insulator–‐semiconductor field‐effect transistor (MISFET) are improved remarkably using AlN/Al 2 O 3 stack gate. Atomic‐layer‐deposited Al 2 O 3 (ALD‐Al 2 O 3 ) is formed on H‐diamond to protect the hole conductive layer at the surface, followed by the sputter‐deposited AlN (SD‐AlN) under mixed Ar+N 2 atmosphere. The insulating property of SD‐AlN under mixed Ar+N 2 atmosphere is highly improved compared with that of SD‐AlN under pure Ar atmosphere. In addition, the positive charges in the SD‐AlN are reduced upon the mixed Ar+N 2 atmosphere sputter condition. These results could be attributed to the improved electrical properties of H‐diamond MISFET and MIS diode with SD‐AlN/ALD‐Al 2 O 3 stack gate. The MIS diode provides a leakage current density as low as ≈1.25 × 10 −6 A cm −2 at gate voltage bias in the range of −20 and +4 V. The capacitance–voltage curve shows an almost no flat‐band voltage shift, and the value of effective dielectric constant of SD‐AlN approaches close to that of bulk AlN. The MISFET shows normally on depletion mode transfer characteristic. The drain–source current maximum, threshold voltage, and maximum extrinsic conductance of the MISFET with 4 μm gate length are around −58.4 mA mm −1 , +1.2 V, and 7.49 mS mm −1 .