Influence of Symmetric Underlap on Analog, RF and Power Applications for DG AlGaN/GaN MOS-HEMT

Abstract

An Underlap Double Gate (U-DG) Symmetric Heterojunction AlGaN/GaN Metal Oxide Semiconductor High Electron Mobility Transistor (MOS-HEMT) with varying source and drain underlap lengths have been studied. The analog performance of the devices has been studied on the basis of parameters like transconductance (gm), transconductance generation factor (gm/ID) and intrinsic gain (gmR0). This paper also depicts the effect of varying underlap lengths on the RF figure of merits (FOMs) such as the total gate capacitance (CGG), cut-off frequency (fT) and maximum frequency of oscillation (fMAX) using non-quasi-static approach. Studies shows that the increase in underlap length in MOS-HEMT decreases the DIBL and Subthreshold Swing. U-DG AlGaN/GaN MOS-HEMT with 300 nm symmetric underlap device shows superior Power Output Efficiency (POE) of 41% compared to the 200 nm underlap structure and 100 nm underlap length with 35% and 33% respectively.