Investigations on highly stable thermal characteristics of a dilute In _0.2Ga_0.8AsSb/GaAs doped-channel field-effect transistor

This work reports for the first time a novel In_0.2Ga _0.8AsSb/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 νm². The proposed design has also shown a stable thermal threshold coefficient (∂V_th/∂T) of -0.7 mV K^-1.