Performance analysis of HfO2/InAlN/AlN/GaN HEMT with AlN buffer layer for high power microwave applications

Abstract

We present a performance enhancement evaluation of n + doped graded InGaN drain/source region-based HfO 2 /InAlN/AlN/GaN/AlN on SiC metal-oxide-semiconductor high electron mobility transistor (MOS-HEMTs) with a T-shaped gate. Impact on the device characteristics with the inclusion of a HfO 2 surface passivation layer and an AlN buffer layer in the MOS-HEMT structure as a performance booster has been analyzed for the HEMT device with 30 nm gate length using Silvaco ATLAS TCAD. The proposed MOS-HEMT exhibits an outstanding performance, with an enhanced power gain cut-off frequency (f max ) of 366 GHz, a current gain cut-off frequency (f t ) of 426 GHz, and a off-state breakdown voltage (V br ) of 81 V. The high -k (high permittivity) HfO 2 based metal oxide semiconductor HEMT device experiences a low off-state gate leakage current (I g ~ 10 −11 A/mm) and a high I on /I off ratio of 10 9 . The InAlN/GaN/AlN heterostructures demonstrate improved two-dimensional electron gas (2DEG ~ 5.3 × 10 13 cm −2 ), carrier mobility (μ) of 1256 Cm 2 /V-s and drain current density of (I ds ) 2.7 A/mm. A large signal analysis performed at 30 GHz yielded a maximum of 28% power-added efficiency. The high JFoM of 34.506 THz V (Johnson Figure of Merit = f t × V br ) and (f t .f max ) 1/2 of 394.86 GHz indicate the potential applicability of the HfO 2 /InAlN/GaN MOS-HEMTs in high-frequency and high-power applications.