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In this work, we report a study of the temperature dependent pulsed current voltage and RF characterization of [Formula: see text]-(Al x Ga 1−x ) 2 O 3 /Ga 2 O 3 hetero-structure FETs (HFETs) before and after silicon nitride (Si 3 N 4 ) passivation. Under sub-microsecond pulsing, a moderate DC-RF dispersion (current collapse) is observed before passivation in gate lag measurements, while no current collapse is observed in the drain lag measurements. The dispersion in the gate lag is possibly attributed to interface traps in the gate–drain access region. DC-RF dispersion did not show any strong dependence on the pulse widths. Temperature dependent RF measurements up to 250 °C do not show degradation in the cutoff frequencies. After Si 3 N 4 deposition at 350 °C, a shift of the threshold voltage is observed which changed the DC characteristics. However, the current collapse is eliminated; at 200 ns pulse widths, a 50% higher current is observed compared to the DC at high drain voltages. No current collapse is observed even at higher temperatures. RF performance of the passivated devices does not show degradation. These results show that ex situ deposited Si 3 N 4 is a potential candidate for passivation of [Formula: see text]-(Al x Ga 1−x ) 2 O 3 /Ga 2 O 3 HFETs. 

High crystalline quality thick β-Ga₂O₃drift layers are essential for multi-kV vertical power devices. Low-pressure chemical vapor deposition (LPCVD) is suitable for achieving high growth rates. This paper presents a systematic study of the Schottky barrier diodes fabricated on four different Si-doped homoepitaxial β-Ga₂O₃thin films grown on Sn-doped (010) and (001) β-Ga₂O₃substrates by LPCVD with a fast growth rate varying from 13 to 21  μm/h. A higher temperature growth results in the highest reported growth rate to date. Room temperature current density–voltage data for different Schottky diodes are presented, and diode characteristics, such as ideality factor, barrier height, specific on-resistance, and breakdown voltage are studied. Temperature dependence (25–250 °C) of the ideality factor, barrier height, and specific on-resistance is also analyzed from the J–V–T characteristics of the fabricated Schottky diodes.