Epitaxial optimization of 130-nm gate-length InGaAs/InAlAs HEMTs for high-frequency applications
Journal article, 2008

In this paper, the influence of epitaxial-layer design on high-frequency properties of 130-nm gate-length InGaAs/InAlAs/InP high-electron-mobility transistors (InP HEMTs) has been investigated. The In channel content ([In]: 53%, 70%, and 80%), the δ-doping concentration (δ: 3, 5, and 7 × 1012 cm-2), and the Schottky-layer thickness (dSL: 9, 11, and 13 nm) have been varied. The maximum frequency of oscillation fmax, the cutoff frequency fT, the drain-to-source current IDS, and the transconductance gm have been analyzed for InP HEMTs. All devices exhibited an increase in IDS with increasing [In], δ, and dSL. An increase in fmax, fT, and gm were observed with increasing [In]. When changing [In] from 53% to 80%, fT and fmax improved by 14% and 21%, respectively. For the δ parameter, an increase in fT and gm was found. However, fmax was drastically reduced for the highest δ. This is suggested to be due to the formation of a parasitic conduction channel located at the doping plane in the HEMT structure for δ ≥ 6.3 × 1012 cm-2. For the dSL parameter, an optimum with respect to fmax, fT, and gm was observed. The optimized HEMT exhibited an extrinsic fT and fmax of 250 and 300 GHz, respectively.


Mikael Malmkvist

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Shu Min Wang

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Jan Grahn

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

IEEE Transactions on Electron Devices

0018-9383 (ISSN) 15579646 (eISSN)

Vol. 55 1 pp. 268-275

Subject Categories

Other Electrical Engineering, Electronic Engineering, Information Engineering



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