InAs Thin-Channel High-Electron-Mobility Transistors with Very High Current-Gain Cutoff Frequency for Emerging Submillimeter-Wave Applications

60 nm InAs high-electron-mobility transistors (HEMTs) with a thin channel, a thin InAlAs barrier layer, and a very high gate stem structure have been fabricated and characterized. The thickness of the channel, as well as that of the InAlAs barrier layer, was reduced to 5 nm. A stem height of 250 nm...

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Published inApplied physics express Vol. 6; no. 3; pp. 034001 - 034001-3
Main Authors Chang, Edward-Yi, Kuo, Chien-I, Hsu, Heng-Tung, Chiang, Che-Yang, Miyamoto, Yasuyuki
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.03.2013
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Summary:60 nm InAs high-electron-mobility transistors (HEMTs) with a thin channel, a thin InAlAs barrier layer, and a very high gate stem structure have been fabricated and characterized. The thickness of the channel, as well as that of the InAlAs barrier layer, was reduced to 5 nm. A stem height of 250 nm with a Pt-buried gate was used in the device configuration to reduce the parasitics. A high DC transconductance of 2114 mS/mm and a current-gain cutoff frequency ($f_{\text{T}}$) of 710 GHz were achieved at $V_{\text{DS}}=0.5$ V.
Bibliography:Schematic view of thin-channel InAs HEMT structure. The inset SEM images are the high-stem T-gate. (a) Drain--source current versus drain--source voltage curve for 60 nm device; (b) output conductance as a function of drain current for various channel-thicknesses. Transconductance versus gate--source voltage with 60 and 100 nm gate lengths. The inset figure is the Schottky gate leakage current for these fabricated devices. (a) Frequency dependence of the current gain ($H_{21}$), Mason's unilateral gain ($U$), maximum stable gain (MSG), and stability factor ($K$) at $V_{\text{DS}}=0.5$ V and $V_{\text{GS}}=0.25$ V. The predictions of the equivalent circuit model are also included. (b) Slope of the imaginary component of the reciprocal of the current gain versus frequency, taken from the low-frequency portion of the measurement range.
ISSN:1882-0778
1882-0786
DOI:10.7567/APEX.6.034001