Degradation of Ka-Band GaN LNA Under High-Input Power Stress: Experimental and Theoretical Insights

A 23–30-GHz gallium nitride (GaN) low-noise amplifier (LNA) with a noise figure (NF) of 0.87–1.51 dB is presented in this article. This LNA was fabricated with 100-nm gate-length GaN-on-silicon (GaN/Si) microwave monolithic integrated circuit (MMIC) process. The linear gain is 14–17 dB within the band. For investigating the robustness of this LNA, 1-W continuous wave (CW) at 27 GHz was stressed on the input port of the LNA. The gain decreased, and the NF increased after stress. Experimental research and first-principles calculations were carried out to investigate the physical origin of the degradation. The dehydrogenation of $\text{V}_{{\text {Ga}}}$ -H3 complexes causes the decrease of gain, and the creation of $\text{V}_{{\text {Al}}}$ -H4 in the AlN barrier is supposed to cause an increase of NF.