Negative differential resistance observation and a new fitting model for electron drift velocity in GaN-based heterostructures
Author
Atmaca, G.
Narin, P.
Kutlu, E.
Malin, T. V.
Mansurov, V. G.
Zhuravlev, K. S.
Lişesivdin, S. B.
Özbay, Ekmel
Date
2018Source Title
IEEE Transactions on Electron Devices
Print ISSN
0018-9383
Publisher
Institute of Electrical and Electronics Engineers
Volume
65
Issue
3
Pages
950 - 956
Language
English
Type
ArticleItem Usage Stats
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Abstract
The aim of this paper is an investigation of electric field-dependent drift velocity characteristics for Al0.3Ga0.7N/AlN/GaN heterostructures without and with in situ Si3N4 passivation. The nanosecond-pulsed current-voltage ( {I}-{V} ) measurements were performed using a 20-ns applied pulse. Electron drift velocity depending on the electric field was obtained from the {I}-{V} measurements. These measurements show that a reduction in peak electron velocity from \text {2.01} \times \text {10}^{\text {7}} to \text {1.39} \times \text {10}^{\text {7}} cm/s after in situ Si3N4 passivation. Also, negative differential resistance regime was observed which begins at lower fields with the implementation of in situ Si3N4 passivation. In our samples, the electric field dependence of drift velocity was measured over 400 kV/cm due to smaller sample lengths. Then, a well-known fitting model was fitted to our experimental results. This fitting model was improved in order to provide an adequate description of the field dependence of drift velocity. It gives reasonable agreement with the experimental drift velocity data up to 475 kV/cm of the electric field and could be used in the device simulators.
Keywords
2-dimensional electron gas (2DEG)AlGaN
Drift velocity
Gallium nitride (GaN)
Negative differential resistivity (NDR)
SiN passivation