Modelling of fin width dependent threshold voltage in fin shaped nano channel AlGaN/GaN HEMT. (May 2020)

• Record Type: Journal Article
• Authors: Chakrabarty, A.; Swain, R.
• Is Part Of: Superlattices and microstructures. Volume 141(2020)
• Publication Date: 2020-05
• Subjects: 2DEG -- FinHEMT -- Fin width -- Strain relaxation -- Threshold voltage; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2020.106497
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: A systematic theoretical model of threshold voltage ( V T ) for AlGaN/GaN fin shaped nano channel HEMT (FinHEMT) structure has been proposed. This device can achieve enhancement mode operation with decreased fin width ( W fin ). This proposed model captures the decreased two dimensional electron gas ( 2DEG ) density due to combined effect of built-in partial strain relaxation and partial side wall depletion ( W depl ) of nano channel due to surface potential of sidewalls. This leads to positive V T which varies inversely with W fin . This influence indicates that narrower fin width below 60 nm contributes to a stable positive threshold voltage. Highlights: Compact model for VT of a normally-off Fin shaped nanostructure AlGaN/GaN HEMT is developed. The developed model outcomes are compared with existing experimental values from literature. Threshold voltage of 0.8V is obtained with 60 nm Fin width. A thin Fin width and suitable Al mole fraction play important role for achieving normally-off operation.