Microwave noise characteristics of AlGaN/GaN HEMTs on SiC substrates for broad-band low-noise amplifiers

This letter reports high-performance passivated AlGaN/GaN high electron-mobility transistors (HEMTs) with 0.25-/spl mu/m gate-length for low noise applications. The devices exhibited a minimum noise figure (NF/sub min/) of 0.98 dB and an associated gain (G/sub a/) of 8.97 dB at 18 GHz. The noise resistance (R/sub n/), the measure of noise sensitivity to source mismatch, is 31/spl Omega/ at 18 GHz, which is relatively low and suitable for broad-band low noise amplifiers. The noise modeling analysis shows that the minimum noise figure of the GaN HEMT can be reduced further by reducing noise contributions from parasitics. These results demonstrate the viability of AlGaN/GaN HEMTs for low-noise as well as high power amplifiers.