Enhancement-Mode Gate-Recess-Free GaN-Based p-Channel Heterojunction Field-Effect Transistor with Ultra-Low Subthreshold Swing

We report enhancement-mode {p} -channel heterojunction field-effect transistors (HFETs) without gate recess on a standard {p} -GaN/AlGaN/GaN high electron mobility transistor (HEMT) platform. The {p} -GaN in the gate region was partially passivated by a low-power hydrogen plasma treatment process, and the remaining active {p} -GaN and the underlying AlGaN formed the {p} -channel. The device showed a record low off-state leakage of < 10 {\text {-8}} A/mm and subthreshold swing (SS) of 123.0 mV/dec with a threshold voltage ( {V} {\text {th}} ) of -0.6 V and high-temperature stability up to 200 °C. These results indicate that the hydrogen plasma treatment is beneficial for suppressing leakages and preserving excellent material quality in the {p} -channel. With the success of the {p} -HFETs, the {p} -GaN/AlGaN/GaN platform can enable the monolithic integration of GaN {n} - and {p} -channel transistors without the need for regrowth. This work represents a significant step towards the implementation of the GaN CMOS technology.