High-[Formula Omitted] High Johnson's Figure-of-Merit 0.2- [Formula Omitted] Gate AlGaN/GaN HEMTs on Silicon Substrate With [Formula Omitted] Passivation

This letter reports a 0.2-[Formula Omitted] gate AlGaN/GaN high-electron-mobility transistors (HEMTs) on an Si substrate passivated with an [Formula Omitted] (4/20 nm) stack layer. The 4-nm-thick AlN was grown by plasma-enhanced atomic-layer-deposition. The [Formula Omitted]-passivated HEMTs exhibit a high maximum drain current of 930 mA/mm, an three-terminal OFF-state breakdown voltage [Formula Omitted] of 119 V, and a small threshold voltage shift of 130 mV in a wide drain bias range [Formula Omitted]. Owing to the additional positive polarization charge in the AlN passivation layer, the access resistance [Formula Omitted] in the GaN-on-Si HEMTs is significantly reduced while maintaining small parasitic gate-drain capacitance [Formula Omitted], contributing to a high power-gain cutoff frequency [Formula Omitted] of 182 GHz and a high Johnson's figure of merit of [Formula Omitted] of [Formula Omitted] simultaneously. The accuracy of the RF performance is verified by a small signal modeling based on measured S-parameters. [PUBLICATION ABSTRACT]