Performance analysis of 20 nm gate-length In0.2Al0.8N/GaN HEMT with Cu-gate having a remarkable high ION/IOFF ratio

Abstract

We propose a new structure of InxAl1−xN/GaN high electron mobility transistor (HEMT) with gate length of 20 nm. The threshold voltage of this HEMT is achieved as −0.472 V. In this device the InAlN barrier layer is intentionally n-doped to boost the ION/IOFF ratio. The InAlN layer acts as donor barrier layer for this HEMT which exhibits an ION = 10−4.3 A and a very low IOFF = 10−14.4 A resulting in an ION/IOFF ratio of 1010.1. We compared our obtained results with the conventional InAlN/GaN HEMT device having undoped barrier and found that the proposed device has almost 105 times better ION/IOFF ratio. Further, the mobility analysis in GaN channel of this proposed HEMT structure along with DC analysis, C–V and conductance characteristics by using small-signal analysis are also presented in this paper. Moreover, the shifts in threshold voltage by DIBL effect and gate leakage current in the proposed HEMT are also discussed. InAlN was chosen as the most preferred barrier layer as a replacement of AlGaN for its excellent thermal conductivity and very good scalability.