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Temperature dependence of the I–V characteristics of Ni/Au Schottky contacts to AlGaN/GaN heterostructures grown on Si substrates
Author(s) -
Greco G.,
Di Franco S.,
Iucolano F.,
Giannazzo F.,
Roccaforte F.
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.201600764
Subject(s) - heterojunction , thermionic emission , materials science , schottky barrier , optoelectronics , schottky diode , diode , condensed matter physics , barrier layer , rectangular potential barrier , wide bandgap semiconductor , electric field , electron , nanotechnology , layer (electronics) , physics , quantum mechanics
The forward current–voltage ( I–V ) characteristics of Ni/Au Schottky contacts on AlGaN/GaN heterostructures have been studied in this work. The electrical characteristics exhibited a strongly non‐ideal behavior that could not be described by the thermionic emission theory. Hence, we used a “two diodes model,” considering both the presence of the Ni/AlGaN barrier and of a second barrier height at the AlGaN/GaN heterojunction. Capacitance–voltage ( C–V ) measurements enabled us to experimentally determine the properties of the two dimensional electron gas (2DEG) and, hence, of the second barrier at the AlGaN/GaN interface. Following this approach, the anomalous I–V curves could be explained. Moreover, the value of the barrier height at zero‐electric field (flat‐band barrier height) was introduced and determined with this procedure, and resulted in a good agreement with literature data based on photoemission measurements. This approach provides a valid procedure for an accurate determination of the barrier height in AlGaN/GaN heterostructures, and the results can have useful implications for the fabrication of AlGaN/GaN HEMTs devices.