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Proceedings Paper

AlxIn1-xN/GaN heterostructure field effect transistors
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Paper Abstract

In AlGaN/GaN heterostructure field effect transistors (HFETs), two-dimensional-electron-gas (2DEG), induced by strong piezoelectric and spontaneous polarization field, has high sheet density, and can be tuned up to 5 ×1013 cm-2 with pure AlN barrier.[Appl. Phys. Lett. 90, 182112 (2007)].For Al compositions larger than 40%, due to the large lattice mismatch between GaN and AlGaN, strain-related issues significantly reduce the mobility for these high sheet carrier densities. Recently, using nearly lattice-matched AlInN/GaN to improve the performance of HFETs has been studied theoretically and experimentally. A high sheet density (2.42 ×1013 cm2) with >1000 cm2/Vs mobility has been reported by inserting an AlN spacer layer between the AlGaN barrier and GaN channel. However, low-temperature mobilities for AlInN/GaN HFETs are much lower than those for AlGaN/GaN HFETs. In this paper, we study the Al1-xInxN/AlN/GaN (x=0.20 - 0.12) (HFETs) grown by metalorganic chemical vapor deposition. Reduction of In composition from 20% to 12% increased the room temperature equivalent two-dimensional-electron-gas (2DEG) density from 0.90×1013 cm-2 to 1.64 ×1013 cm-2 with corresponding electron mobilities of 1600 cm2/Vs and 1410 cm2/Vs. Furthermore, at 10 K, the mobility reached 17,600 cm2/Vs with a sheet density 9.6 ×1012 cm-2 for the nearly lattice-matched Al0.82In0.18N /AlN/GaN heterostructure. The HFETs having 1 μm gate length exhibited a maximum transconductance of ~ 250 mS/mm with good pinch-off characteristics.

Paper Details

Date Published: 15 February 2008
PDF: 6 pages
Proc. SPIE 6894, Gallium Nitride Materials and Devices III, 68941R (15 February 2008); doi: 10.1117/12.771297
Show Author Affiliations
J. Xie, Virginia Commonwealth Univ. (United States)
X. Ni, Virginia Commonwealth Univ. (United States)
M. Wu, Virginia Commonwealth Univ. (United States)
J. H. Leach, Virginia Commonwealth Univ. (United States)
Ü. Özgür, Virginia Commonwealth Univ. (United States)
H. Morkoç, Virginia Commonwealth Univ. (United States)

Published in SPIE Proceedings Vol. 6894:
Gallium Nitride Materials and Devices III
Hadis Morkoç; Cole W. Litton; Jen-Inn Chyi; Yasushi Nanishi; Euijoon Yoon, Editor(s)

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