Investigations on highly stable thermal characteristics of a dilute In_0.2Ga_0.8AsSb/GaAs doped-channel field-effect transistor

Abstract

This work reports for the first time a novel In 0.2 Ga 0.8 AsSb/GaAs heterostructure doped-channel field-effect transistor (DCFET) grown by the molecular beam epitaxy system. The interfacial quality within the InGaAsSb/GaAs quantum well of the DCFET device has been effectively improved by introducing surfactant-like Sb atoms during the growth of the Si-doped InGaAs channel layer. The improved device characteristics include the peak extrinsic transconductance (g m, max ) of 161.5 mS mm −1 , the peak drain-source saturation current density (I DSS, max ) of 230 mA mm −1 , the gate-voltage swing (GVS) of 1.65 V, the cutoff frequency (f T ) of 12.5 GHz and the maximum oscillation frequency (f max ) of 25 GHz at 300 K with the gate dimensions of 1.2 × 200 µm 2 . The proposed design has also shown a stable thermal threshold coefficient (∂V th /∂T) of −0.7 mV K −1 .

Gate voltage swing enhancement of InGaP/InGaAs pseudomorphic HFET with low-to-high double doping channels

“…A variable HFET, i.e. doping-channel FET (DCFET), has been demonstrated to exhibit broad gate voltage swing for improving device linearity and reducing the higher order harmonic terms in linear amplifier applications [4,5]. The basic structure of DCFETs consists of a narrow bandgap doped material as the channel layer to enhance carrier conduction and a wide bandgap undoped (or low-doping) barrier layer as an 'insulator' to improve the gate Schottky characteristic.…”