摘要
In this study, we report a novel structure of enhancement-mode metal-insulator-semiconductor high electron mobility transistor (E-mode MIS HEMT) with {p} -GaN gate by gate-all-around technology. The gate-all-around structure is fabricated by depositing an insulator and gate to surround the {p} -GaN mesa. The {p} -GaN length is smaller than the gate length, which would easily turn on the two dimensional electron gas (2DEG) of channel and result in a higher drain current and thus improve the device performance. The gate-all-around {p} -GaN MIS HEMT has better gate control, better transconductance, and lower gate leakage current. The device exhibits a threshold voltage ( text{V}-{text {th}} ) of 1.5 V, a maximum transconductance ( text{G}-{text {m.max}} ) of 101 mS/mm, and a drain saturation current density ( text{J}-{text {DS, max}} ) of 412 mA/mm at a gate bias ( text{V}-{text {g}} ) of 5 V. The most important achievement is that the gate leakage current at text{V}-{text {g}}= 5 V is only 10 -8 mA/mm. Moreover, the ratio of drain current density to gate leakage current density ( text{J}-{text {DS}}/text{J}-{text {GS}} ) is 10 8 at text{V}-{text {g}}= 5 V. Finally, the cut-off frequency ( text{f}-{text {t}} ) and maximum oscillation frequency ( text{f}-{text {max}} ) of microwave performance for this gate-all-around device with a 1~mu text{m} gate length are 6.0 and 9.8 GHz, respectively.