DC , Small Signal and Noise Analysis of Graded‐ AlGaN /ε‐Ga2O3 Barrier GaN HEMT on β‐Ga2O3 Substrate for LNAs

This work presents detailed analysis of a graded‐AlGaN/‐GaO/GaN HEMT on a ‐GaO substrate. The incorporation of ‐GaO as a barrier layer significantly enhances the DC, RF, small‐signal and noise performance of the device. TCAD simulation results demonstrate a positive shift in threshold voltage and suppression of OFF‐state leakage current due to enhanced polarization effects and the formation of a two‐dimensional hole gas (2DHG) at the ‐GaO/AlGaN interface. A peak transconductance of 570.55 mS/mm is achieved, marking a 61.69% improvement over the graded‐AlGaN/GaN HEMT. The proposed device exhibits reduced gate–source and gate–drain capacitances, leading to improved electrostatic control and minimized parasitic effects. As a result, 39.98% enhancement in cut‐off frequency (79.08 GHz) and a 42.93% increase in maximum frequency of oscillation (151.14 GHz) is obtained. Small‐signal analysis based on S‐parameters reveals lower input and output reflection coefficients ( & ), enhanced forward gain () and improved RF stability factor (k) which ensures superior impedance matching and signal amplification capability of the proposed device. Furthermore, noise analysis confirms improved low‐noise performance of proposed bilayer barrier HEMT. The device exhibits a 70.31% reduction in noise conductance compared to graded AlGaN barrier HEMT and offers a minimum noise figure of 1.25 dB. It also exhibits improved auto‐correlation of 244.64% (real) and 61.50% (imaginary) and cross‐correlation of 111.10% (input) and 460.49% (output), which is attributed to reduced scattering effects. These results highlight the graded‐AlGaN/‐GaO barrier architecture as a promising alternative for advancing GaN‐based HEMT technology for designing Low noise amplifiers (LNAs).