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
_0.2
Ga
_0.8
AsSb 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 (NH
₄
)
₂
S
_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
<sub>m,

max</sub>
) 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 ¿m
²
.