2019 Compound Semiconductor Week (CSW) | 2019
Pulsed RF Power Measurements of Laterally Scaled Ga2O3 FETs
Abstract
The power switching potential of Ga<inf>2</inf>O<inf>3</inf> has been well established in the last several years due to the material s high critical electric field <tex>$(\\mathrm{E}_{\\mathrm{C}})$</tex> strength. This allows for dramatic device scaling and operation at high voltage with reduced series resistance in power switching applications. The same argument applies for RF power amplification, where the high <tex>$\\mathrm{E}_{\\mathrm{C}}$</tex> of Ga<inf>2</inf>O<inf>3</inf> allows FETs to be scaled to smaller dimensions while operating at higher operating voltages than existing RF FETs. At the same time, ab initio calculations published in 2017 for velocity-field characteristics of Ga<inf>2</inf>O<inf>3</inf> indicate a peak electron velocity of <tex>$2\\mathrm{x}10^{7}$</tex> cm/s which suggests the power-frequency product for Ga<inf>2</inf>O<inf>3</inf> is significantly greater than that of GaN. In 2017, the first demonstrated CW RF operation for Ga<inf>2</inf>O<inf>3</inf> FETs was in part limited by the thermal resistance and immaturity of heat extraction techniques to ~300 mW/mm. Since then, pulsed RF power measurement techniques have been implemented to accelerate electrical characterization of RF Ga<inf>2</inf>O<inf>3</inf> FETs. Pulsed RF output power <tex>$> 500$</tex> mW/mm has been measured at 1 GHz. Advances in laterally scaled devices and topology design to ensure electrons achieve saturated velocity in the channel will be discussed.