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Please use this identifier to cite or link to this item: http://hdl.handle.net/10119/15737

Title: Insulator-semiconductor interface fixed charges in AlGaN/GaN metal-insulator-semiconductor devices with Al_2O_3 or AlTiO gate dielectrics
Authors: Le, Son Phuong
Nguyen, Duong Dai
Suzuki,Toshi-kazu
Keywords: AlGaN/GaN
metal-insulator-semiconductor (MIS) device
interface fixed charges
threshold voltage
Issue Date: 2018-01-19
Publisher: American Institute of Physics
Magazine name: Journal of Applied Physics
Volume: 123
Number: 3
Start page: 034504-1
End page: 034504-7
DOI: 10.1063/1.5017668
Abstract: We have investigated insulator-semiconductor interface fixed charges in AlGaN/GaN metal-insulator-semiconductor (MIS) devices with Al_2O_3 or AlTiO (an alloy of Al_2O_3 and TiO_2) gate dielectrics obtained by atomic layer deposition on AlGaN. Analyzing insulator-thickness dependences of threshold voltages for the MIS devices, we evaluated positive interface fixed charges, whose density at the AlTiO/AlGaN interface is significantly lower than that at the Al_2O_3/AlGaN interface. This and a higher dielectric constant of AlTiO lead to rather shallower threshold voltages for the AlTiO gate dielectric than for Al_2O_3. The lower interface fixed charge density also leads to the fact that the two-dimensional electron concentration is a decreasing function of the insulator thickness for AlTiO, whereas being an increasing function for Al_2O_3. Moreover, we discuss the relationship between the interface fixed charges and interface states. From the conductance method, it is shown that the interface state densities are very similar at the Al_2O_3/AlGaN and AlTiO/AlGaN interfaces. Therefore, we consider that the lower AlTiO/AlGaN interface fixed charge density is not owing to electrons trapped at deep interface states compensating the positive fixed charges and can be attributed to a lower density of oxygen-related interface donors.
Rights: Copyright 2018 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Son Phuong Le, Duong Dai Nguyen, and Toshi-kazu Suzuki, Journal of Applied Physics, 123(3), 034504 (2018) and may be found at http://dx.doi.org/10.1063/1.5017668
URI: http://hdl.handle.net/10119/15737
Material Type: publisher
Appears in Collections:c10-1. 雑誌掲載論文 (Journal Articles)

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