High-frequency AlGaN/GaN HFETs with fT/fmax of 149/263 GHz for D-band PA applications

• Published in: Electronics letters Vol. 52; no. 15; pp. 1340 - 1342
• Main Authors: Lv, Yuanjie, Song, Xubo, Guo, Hongyu, Fang, Yulong, Feng, Zhihong
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 21.07.2016
• Subjects: AlGaN‐GaN; aluminium compounds; distance 600 nm; D‐band PA application; D‐band power‐amplifier application; frequency 110 GHz to 170 GHz; frequency 263 GHz; gallium compounds; gate recess; high electron mobility transistors; high‐frequency HFET; high‐unity current gain cut‐off frequency; III‐V semiconductors; maximum oscillation frequency; millimetre wave field effect transistors; millimetre wave power amplifiers; nonalloyed regrown ohmic contacts; record extrinsic transconductance; record‐high value; scaled heterostructure field‐effect transistors; scaled source‐to‐drain distance; silicon carbide substrate; size 60 nm; T‐shaped HFET; wide band gap semiconductors; Wireless communications; record extrinsic transconductance; D-band PA application; distance 600 nm; scaled source-to-drain distance; millimetre wave field effect transistors; T-shaped HFET; D-band power-amplifier application; high-frequency HFET; AlGaN-GaN; millimetre wave power amplifiers; aluminium compounds; gate recess; record-high value; size 60 nm; gallium compounds; high electron mobility transistors; scaled heterostructure field-effect transistors; high-unity current gain cut-off frequency; maximum oscillation frequency; silicon carbide substrate; frequency 263 GHz; frequency 110 GHz to 170 GHz; wide band gap semiconductors; nonalloyed regrown ohmic contacts; III-V semiconductors
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2016.1241

Scaled AlGaN/GaN heterostructure field-effect transistors (HFETs) with high unity current gain cut-off frequency (fT) and maximum oscillation frequency (fmax) were fabricated and characterised on SiC substrate. In the device, scaled source-to-drain distance (Lsd) of 600 nm was realised by employing non-alloyed regrown n+-GaN ohmic contacts. A 60 nm T-shaped AlGaN/GaN HFETs showed excellent DC and RF performance after gate recess. A record extrinsic transconductance (gm) of 764 mS/mm was obtained in the AlGaN/GaN HFETs. Moreover, the maximum fT and fmax of the fabricated device reach to 149 and 263 GHz at the same bias, exhibiting a record-high value of fT*fmax. This indicates that the AlGaN/GaN HFETs still have the potential for D-band (110–170 GHz) power-amplifier application with further optimisation.