20 nm Metamorphic HEMT with 660 GHz FT

Conference: IPRM 2011 - 23th International Conference on Indium Phosphide and Related Materials
05/22/2011 - 05/26/2011 at Berlin, Germany

Proceedings: IPRM 2011

Pages: 4Language: englishTyp: PDF

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Leuther, A.; Tessmann, A.; Kallfass, I.; Massler, H.; Loesch, R.; Schlechtweg, M.; Ambacher, O. (Fraunhofer Institute for Applied Solid State Physics (IAF), Tullastrasse 72, 79108 Freiburg, Germany)
Koch, S.; Merkle, T.; Saito, S. (Sony Deutschland GmbH, Sensing Systems Laboratory, Hedelfinger Strasse 61, 70327 Stuttgart, Germany)

A metamorphic HEMT MMIC technology with 20 nm gate length is presented, developed for the fabrication of terahertz-wave monolithic integrated circuits (TMICs) with operational frequencies beyond 500 GHz. The MBE grown transistor heterostructure comprises a strained In0.8Ga0.2As channel with high electron mobility and high electron density for proper device scaling. The realized mHEMTs achieve a source resistance RS of 0.1 Ohmmm which is required to minimize resistive losses in combination with an extrinsic maximum transconductance gm_max of 2500 mS/mm. The output characteristics of the 20 nm devices show no short channel effects and demonstrate sufficient pinch-off behavior for analog applications. For a transistor with 2 x 10 µm gate width a cut-off frequency fT of 660 GHz was extrapolated which is to our knowledge the highest published fT for any HEMT device. The presented 20 nm mHEMT technology was employed for the design of a compact four stage lownoise amplifier (LNA). The total small signal gain of the LNA exceeds 20 dB from 115 - 175 GHz.