First Demonstration of State-of-the-art GaN HEMTs for Power and RF Applications on A Unified Platform with Free-standing GaN Substrate and Fe/C Co-doped Buffer

In this paper, we report excellent power and radio frequency (RF) performances of GaN HEMTs grown on free-standing GaN substrate using a unified Fe/C co-doped GaN buffer. With gate-drain distance ($L_{\mathrm{gd}}$) of 6.35 $\mu$m, the device presented a low specific on-resistance ($R_{\mathrm{on}_{-}\mathrm{sp}}$) of 0.66 m$\Omega\cdot\mathrm{cm}^{2}$ and a high breakdown voltage ($V_{\mathrm{BR}}$) of 710 V. Record Johnson’s figure-of-merit (JFOM) of 16.25 THz$\cdot$V and $f_{\max}$. VBR of 38.34 THz$\cdot$V were achieved among GaN HEMTs. Load-pull measurements reveal a state-of-the-art power density of 10.2 W/mm for GaN-on-GaN HEMTs. Moreover, the GaN-on-GaN HEMTs in this work show excellent reliability and stable Schottky characteristics after the reverse gate step stress. This technology provides a unified design of material and process for GaN power and RF devices with high performance, promoting the integration of GaN-based devices on the same platform.