Electrical characteristics of metal–semiconductor–metal (MSM) varactors fabricated on In 0.53 Ga 0.47 As/InAs/In 0.53 Ga 0.47 As composite channel HEMT structure

• Published in: Japanese Journal of Applied Physics 2023-01, Vol.62 (1), p.10906
• Main Authors: Shim, Jae-Phil, Jang, Hyunchul, Kim, Do-Kywn, Shin, Seung Heon
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.35848/1347-4065/acb11d

In this paper, we have fabricated and characterized metal–semiconductor–metal (MSM) varactors with gate lengths ranging from 120, 180, and 290 nm on In 0.53 Ga 0.47 As/InAs/In 0.53 Ga 0.47 As composite channel high electron mobility transistor structure. We applied the buried-Pt gate technology to study the electrical characteristics of the MSM varactors depending on the gate-to-channel distance. The fabricated MSM varactors exhibited a cutoff frequency of 185 GHz for annealed varactors and 174 GHz for non-annealed varactors with L g of 120 nm, respectively. Also, non-annealed MSM varactors show an excellent capacitance ratio (= C max / C min ) of 5.1 with L g of 290 nm, this is because of the longer gate-to-channel distance compared to annealed MSM varactors. The figure of merit (FOM = f 0 · C max / C min ) of the MSM varactors, which represents the performance of the MSM varactors, shows 451 and 438 for non-annealed and annealed devices, respectively.