Fabrication of AlGaN/GaN Fin-Type HEMT Using a Novel T-Gate Process for Improved Radio-Frequency Performance

• Published in: IEEE access 2020, Vol.8, p.139156-139160
• Main Authors: Cho, Min Su, Seo, Jae Hwa, Lee, Sang Ho, Jang, Hwan Soo, Kang, In Man
• Format: Article
• Language: English
• Subjects: Aluminum gallium nitride; Aluminum gallium nitrides; E-beam lithography; FinFET; Gallium compounds; Gallium nitride; Gallium nitrides; HEMTs; high electron mobility transistor; High electron mobility transistors; Leakage current; Logic gates; maximum oscillation frequency; nanofabrication; nanolithography; Performance evaluation; Photoresists; Radio frequency; Semiconductor devices; T-gate; Wide band gap semiconductors
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2020.3011103

To increase the radio-frequency (RF) performance of AlGaN/GaN-based fin-type high electron mobility transistors (HEMTs), a novel T-gate process was developed and applied to fabricate a device with high RF performance. In a single lithography process, the applied T-gate process shows a technique for forming a T-gate using the reactivity difference of several photoresists. The fabricated device has a steep fin width (W fin ) of 130 nm, a fin height (H fin ) of 250 nm, and a gate length (L G ) of 190 nm. The device exhibits a low leakage current (I off ) of 6.6\times 10^{-10} A/mm and a high I on /I off current ratio of 4.7\times 10^{8}_{.} Moreover, the fabricated device achieved a high cut-off frequency (f T ) of 9.7 GHz and a very high maximum oscillation frequency (f max ) of 27.8 GHz. The f max value of the proposed device is 138% higher than that of GaN-based fin-type HEMTs without T-gate.