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In this work, an enhancement-mode (E-mode) β-Ga2O3 metal-oxide-semiconductor field-effect transistor (MOSFET) has been achieved by incorporating a laminated-ferroelectric charge storage gate (L-FeG) structure [Al2O3/HfO2/Al2O3/Hf0.5Zr0.5O2 (HZO) of 10/5/2/16 nm]. The band diagram between L-FeG dielectrics (Al2O3, HfO2, and HZO) and β-Ga2O3 was determined by x-ray photoelectron spectroscopy. After applying a gate pulse with an intensity of +18 V and width of 1 ms, the saturation current of the E-mode device was measured to be 23.2 mA/mm, which shows a negligible current reduction compared to that of 22.1 mA/mm in a depletion- (D-) mode device. In addition, the threshold voltage (VTH) is only shifted by 2.76% and 2.18%, respectively, after applying the gate stress and gate-drain stress of 15 V for 104 s. Meanwhile, a high breakdown voltage of 2142 V and specific on-resistance (RON,sp) of 23.84 mΩ·cm2 were also achieved, which correspond to a state-of-art high power figure of merit of 192.5 MW/cm2, showing the great potential of combing the ferroelectric gate stack and lateral Ga2O3 MOSFET as next generation power devices.

Herein, a high‐performance β‐gallium oxide (β‐Ga2O3) metal–oxide–semiconductor field‐effect transistor (MOSFET) on sapphire substrate with a high breakdown voltage of more than 800 V and a high‐power figure of merit of more than 86.3 MV cm−2 is demonstrated. The atomic force microscopy (AFM) image and Raman peaks that are first characterized to ensure a nanomembrane with high quality are used for the device fabrication. A saturation drain current of 231.8 mA mm−1, an RON,sp of 7.41 mΩ cm2, an ON/OFF ratio of 108, and a subthreshold swing of 86 mV dec−1 are obtained at a channel doping concentration of 4.47 × 1017 cm−3 and a source‐to‐drain distance of 11.4 μm. Furthermore, a high breakdown voltage over 800 V is also achieved, corresponding to a record‐high direct current (DC) power figure of merit of 86.3 MW cm−2. Technology computer aided design (TCAD) simulation is also performed to extract the distribution of the electric field along the β‐Ga2O3 channel surface.

We studied the reverse current emission mechanism of the Mo/β-Ga2O3 Schottky barrier diode through the temperature-dependent current-voltage (I-V) characteristics from 298 to 423 K. The variation of reverse current with the electric field indicates that the Schottky emission is the dominant carrier transport mechanism under reverse bias rather than the Frenkel–Poole trap-assisted emission model. Moreover, a breakdown voltage of 300 V was obtained in Fluorinert ambient with an average electric field of 3 MV/cm in Mo/β-Ga2O3 Schottky barrier diode. The effects of the surface states, on the electric field distribution, were also analyzed by TCAD simulation. With the negative surface charge densities increasing, the peak electric field reduces monotonously. Furthermore, the Schottky barrier height inhomogeneity under forward bias was also discussed.