Performance assessment and sub-threshold analysis of gate material engineered AlGaN/GaN HEMT for enhanced carrier transport efficiency

The present work explores the features of gate material engineered (GME) AlGaN/GaN high electron mobility transistor (HEMT) for enhanced carrier transport efficiency (CTE) and suppressed short channel effects (SCEs) using 2-D sub-threshold analysis and device simulation. The model accurately predicts the channel potential, electric field and sub-threshold current for the conventional and GME HEMT, taking into account the effect of work function difference of the two metal gates. This is verified by comparing the model results with the ATLAS simulation results. Further, simulation study has been extended to reflect the wide range of benefits exhibited by GME HEMT for its on-state and analog performance. The simulation results demonstrate that the GME HEMT exhibits much higher on current, lower conductance and higher transconductance as compared to the conventional HEMT due to improved CTE and reduced SCEs. This in turn has a direct bearing on the device figure of merits (FOMs) such as intrinsic gain, device efficiency and early voltage. Tuning of GME HEMT in terms of the relative lengths of the two metal gates, their work function difference and barrier layer thickness has further been carried out to enhance the drive current, transconductance and the device FOMs illustrating the superior performance of GME HEMT for future high-performance high-speed switching, digital and analog applications.