The effect of the gate-drain distance on high frequency and noise performance for AlGaN/GaN HEMT

The influence of the gate-drain distance on high frequency and noise performance of AlGaN/GaN high electron mobility transistors (HEMT) is investigated in this article. AlGaN/GaN HEMTs with three different gate-drain separation structures are fabricated using 0.25 μm gatelength process, and a detailed comparative study on their device performances is performed. Small signal model parameters are determined from S-parameter on-wafer measurement up to 40 GHz, and the noise parameters are determined up to 18 GHz based on 50 Ω noise figure on-wafer measurement system. The variation of intrinsic small signal model parameters and noise model parameters with different gate-drain separation is studied.