RF characteristics of 150‐nm AlGaN/GaN high electron mobility transistors fabricated using i‐line stepper lithography

• Published in: Electronics letters 2023-05, Vol.59 (10), p.n/a
• Main Authors: Ando, Yuji, Takahashi, Hidemasa, Makisako, Ryutaro, Wakejima, Akio, Suda, Jun
• Format: Article
• Language: English
• Subjects: Aluminum gallium nitrides; Electrodes; Electrons; Equivalent circuits; Gallium nitrides; High electron mobility transistors; Lithography; microwave amplifiers; millimetre‐wave amplifiers; Semiconductor devices; Transistors; wide band gap semiconductors
• ISSN: 0013-5194; 1350-911X
• DOI: 10.1049/ell2.12798

This article reports radio frequency characteristics of 150‐nm gate aluminum gallium nitride (AlGaN)/gallium nitride (GaN) high electron mobility transistors (HEMTs) fabricated using i‐line stepper lithography and a thermal reflow technique. The authors have developed two different gate structures that were a field‐plated gate using the lift‐off process and a Y‐shaped gate using the ion‐milling process. Fabricated HEMTs using these different gate structures exhibited nearly equivalent DC characteristics. The field‐plated gate device showed a unity current gain cutoff frequency (fT) of 35 GHz and a maximum oscillation frequency (fmax) of 106 GHz, while the Y‐shaped gate device showed fT of 36 GHz and fmax of 115 GHz. The equivalent circuit analysis indicated a decrease in the gate‐drain capacitance and the drain conductance is responsible for the improved fmax in the Y‐shaped gate device. This article reports radio frequency characteristics of 150‐nm gate aluminum gallium nitride (AlGaN)/gallium nitride (GaN) high electron mobility transistors (HEMTs) fabricated using i‐line stepper lithography and a thermal reflow technique.