High-performance double-recessed enhancement-mode metamorphic HEMTs on 4-in GaAs substrates

• Published in: IEEE electron device letters Vol. 24; no. 3; pp. 135 - 137
• Main Authors: Dumka, D.C., Tserng, H.Q., Kao, M.Y., Beam, E.A., Saunier, P.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2003; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cutoff frequency; Devices; Drains; Gallium arsenide; Gallium arsenides; Gates; High electron mobility transistors; Indium compounds; Indium gallium arsenide; Indium gallium arsenides; Metamorphic; mHEMTs; Molecular beam epitaxial growth; Radio frequency; Substrates; Threshold voltage; Transconductance
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2003.809048

Enhancement-mode InAlAs/InGaAs/GaAs metamorphic HEMTs with a composite InGaAs channel and double-recessed 0.15-μm gate length are presented. Epilayers with a room-temperature mobility of 10 000 cm 2 /V-s and a sheet charge of 3.5×10/sup 12/cm/sup -2/ are grown using molecular beam epitaxy on 4-in GaAs substrates. Fully selective double-recess and buried Pt-gate processes are employed to realize uniform and true enhancement-mode operation. Excellent dc and RF characteristics are achieved with threshold voltage, maximum drain current, extrinsic transconductance, and cutoff frequency of 0.3 V, 500 mA/mm, 850 mS/mm, and 128 GHz, respectively, as measured on 100-μm gate width devices. The load pull measurements of 300-μm gate width devices at 35 GHz yielded a 1-dB compression point output power density of 580 mW/mm, gain of 7.2 dB, and a power-added efficiency of 44% at 5 V of drain bias.