This work reports, high electron mobility transistors (HEMTs) using a dilute antimony In0.2Ga0.8AsSb 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)2Sx passivation (sample A), silicon nitride (SiNx) surface passivation (sample B), or without passivation (sample C) have been investigated. Sample A (B/C) has demonstrated superiorly the maximum extrinsic trans-conductance (gm, 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.