Pulsed Power Performance of β-Ga₂O₃ MOSFETs at L-Band

Neil A Moser,Steve Tetlak,Kyle J Liddy,Kevin D Leedy,Nicholas C Miller,Tadj Asel,Shin Mou,Andrew J Green,Gregg H Jessen,Adam Neal,Kelson D Chabak,Dennis E Walker,Miles Lindquist

doi:10.1109/led.2020.2993555

Abstract

DC, small, and large signal results are shown under continuous wave and pulsed conditions for a β-Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> metal-oxide-semiconductor field-effect transistor operating at 1 and 2 GHz. The device has a maximum transducer gain, maximum output power, and peak power added efficiency of 13 dB (15 dB), 715 mW/mm (487 mW/mm), and 23.4% (21.2%), respectively at 1 GHz (2 GHz). We observe the continuous wave output power is limited to 213 mW/mm by drain dispersion likely from surface or interface traps in the gate-drain region as indicated by pulsed IV measurements. High parasitic resistances, as indicated by high knee voltages, also limit the power performance under continuous and pulsed large signal conditions.

Highlights

B ETA-PHASE gallium oxide (β-Ga2O3) metal-oxidesemiconductor field-effect transistors (MOSFETs) are promising power devices due to high projected critical field strength, Ecrit, of ∼8MV/cm [1], [2] and experimental Ecrit of >3.8 MV/cm [3]
[4]–[6], but it has been noted that high Ecrit allows for aggressive scaling of devices which can lead to a high RF figures of merit (FoM) for β-Ga2O3 [7]
Β-Ga2O3 RF devices have been reported with RF power gain up to nearly 20 GHz using small signal measurements [8], [9] and with limited gain in large-signal results up to 1 GHz [10], [11]

Summary

Introduction

B ETA-PHASE gallium oxide (β-Ga2O3) metal-oxidesemiconductor field-effect transistors (MOSFETs) are promising power devices due to high projected critical field strength, Ecrit , of ∼8MV/cm [1], [2] and experimental Ecrit of >3.8 MV/cm [3]. Most β-Ga2O3 devices have been reported so far with excellent power switch figures of merit (FoM). [4]–[6], but it has been noted that high Ecrit allows for aggressive scaling of devices which can lead to a high RF FoM for β-Ga2O3 [7]. Β-Ga2O3 RF devices have been reported with RF power gain up to nearly 20 GHz using small signal measurements [8], [9] and with limited gain in large-signal results up to 1 GHz [10], [11]. Due to the low thermal conductivity of β-Ga2O3, pulsed-power measurements provide an important means to evaluate the RF.

Results

Discussion

Conclusion