Investigations on In0.2Ga0.8AsSb/GaAs high electron mobility transistors with gate passivations

This work reports, high electron mobility transistors (HEMTs) using a dilute antimony In_0.2Ga_0.8AsSb channel, grown by molecular beam epitaxy (MBE) system. Introducing the surfactant-like Sb atoms during growth of the InGaAs/GaAs quantum well (QW) was devised to effectively improve the channel confinement capability and the interfacial quality within the InGaAsSb/GaAs QW heterostructure, resulting in enhanced carrier transport property and superior device performances. In comparison, the proposed devices with employing sulfur (NH₄)₂S_x passivation (sample A), silicon nitride (SiN_x) surface passivation (sample B), or without passivation (sample C) have been investigated. Sample A (B/C) has demonstrated superiorly the maximum extrinsic trans-conductance (g_{m, max}) of 221 (205/183) mS/mm, the drain saturation current density (IDSS) of 205 (190/174) mA/mm, the gate-voltage swing (GVS) of 1.105 (1.28/1.482) V, and the P.A.E. characteristic 30.4 (21.4/13) % at 300 K, with the gate dimensions of 1 × 200 ¿m².