Small-Signal Analysis of Channel Resistance R L at Low Gate Bias Voltages in AlGaN/GaN HEMTs

• Published in: IEEE transactions on electron devices 2021-12, Vol.68 (12), p.6033-6038
• Main Authors: Kaushik, Pragyey Kumar, Singh, Sankalp Kumar, Gupta, Ankur, Basu, Ananjan
• Format: Article
• Language: English
• Subjects: Aluminum gallium nitrides; Bias; Gallium nitrides; High electron mobility transistors; Parameters; Small signal analysis; Threshold voltage
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2021.3116533

In this article, we present the effect of low gate bias on [Formula Omitted] in a small-signal model (SSM) and show that the channel resistance has a strong bias dependence. It has been observed that [Formula Omitted] dominates above the threshold voltage ([Formula Omitted]) and insignificant near to the threshold voltage ([Formula Omitted]). Moreover, we show that the channel resistance ([Formula Omitted]) yields a significant change in drain-to-source resistance ([Formula Omitted]) and capacitance ([Formula Omitted]) of 23% and 30%, respectively. It has also been observed that to match the measured intrinsic Y-parameter, [Formula Omitted] is important. An AlGaN/gallium nitride (GaN) high electron mobility transistor (HEMT) device is used with a channel length of [Formula Omitted] and consisting of 2 [Formula Omitted] gate width for the analysis. The effect of [Formula Omitted] in the intrinsic part of the SSM has been verified and the results show good agreement between simulated and measured S-parameters data up to 40 GHz.