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High operating voltage and high power are important developing goals of GaN-based high-electron mobility transistor (HEMT) at present. In this letter, we demonstrated a GaN-based HEMT exhibiting a breakdown voltage of greater than 300 V, an operating voltage of up to 80 V, an output power of up to 750 W, a power-added efficiency (PAE) of 80% and an associated power gain of 16.8 dB at 1.3 GHz. The device simultaneously realizes high voltage, high power, and high PAE, and is suitable for L -band high-power applications. [ABSTRACT FROM PUBLISHER]

The transport mechanism of reverse surface leakage current in the AlGaN/GaN high-electron mobility transistor (HEMT) becomes one of the most important reliability issues with the downscaling of feature size. In this paper, the research results show that the reverse surface leakage current in AlGaN/GaN HEMT with SiN passivation increases with the enhancement of temperature in the range from 298 K to 423 K. Three possible transport mechanisms are proposed and examined to explain the generation of reverse surface leakage current. By comparing the experimental data with the numerical transport models, it is found that neither Fowler–Nordheim tunneling nor Frenkel–Poole emission can describe the transport of reverse surface leakage current. However, good agreement is found between the experimental data and the two-dimensional variable range hopping (2D-VRH) model. Therefore, it is concluded that the reverse surface leakage current is dominated by the electron hopping through the surface states at the barrier layer. Moreover, the activation energy of surface leakage current is extracted, which is around 0.083 eV. Finally, the SiN passivated HEMT with a high Al composition and a thin AlGaN barrier layer is also studied. It is observed that 2D-VRH still dominates the reverse surface leakage current and the activation energy is around 0.10 eV, which demonstrates that the alteration of the AlGaN barrier layer does not affect the transport mechanism of reverse surface leakage current in this paper. [ABSTRACT FROM AUTHOR]