Impact of Gate Metal on the Performance of p-GaN/AlGaN/GaN High Electron Mobility Transistors

For conventional GaN-based high electron mobility transistors (HEMTs), the work function of gate metal is critical to electrical parameters, such as OFF-state leakage current, forward operating current, and threshold voltage. A high work function is thus required to maintain Schottky gate contact. I...

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Bibliographic Details
Published inIEEE electron device letters Vol. 36; no. 3; pp. 232 - 234
Main Authors Lee, Finella, Liang-Yu Su, Chih-Hao Wang, Yuh-Renn Wu, Jianjang Huang
Format Journal Article
LanguageEnglish
Published IEEE 01.03.2015
Subjects
Aluminum gallium nitride
enhancement mode
Gallium nitride
HEMT
HEMTs
Logic gates
MODFETs
Nickel
threshold voltage
enhancement mode
HEMT
threshold voltage
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Summary:For conventional GaN-based high electron mobility transistors (HEMTs), the work function of gate metal is critical to electrical parameters, such as OFF-state leakage current, forward operating current, and threshold voltage. A high work function is thus required to maintain Schottky gate contact. In this letter, an enhancement-mode HEMT composed of p-type GaN/AlGaN/GaN was fabricated. Unlike typical HEMTs that the Schottky barrier height is determined by the energy difference between gate metal work function and semiconductor (AlGaN, or GaN) conduction band, the insertion of the p-GaN relieves the constraint of gate metal. In addition, the gate Schottky barrier now correlates to the valence band of the semiconductor. Here we compare the HEMT performance of different gate metals-Ni/Au, Ti/Au, and Mo/Ti/Au. The results reveal that a tradeoff between V TH and output drain current.
ISSN:0741-3106
1558-0563
DOI:10.1109/LED.2015.2395454