Improved high-temperature characteristics of a symmetrically graded AlGaAs/InxGa1-xAs/AlGaAs pHEMT

This work investigates the superior high-temperature and high-linearity characteristics of a double d-doped AlGaAs/InxGa1-xAs/AlGaAs pseudomorphic high electron mobility transistor (pHEMT) with a symmetrically linearly graded InxGa1-xAs channel and a wide energy gap AlGaAs barrier. Distinguished high-temperature device characteristics are presented, including an extrinsic transconductance (g(m,max)) of 182 (223) mS mm(-1), a drain-source saturation current density (IDSS) of 428 (524) mA mm(-1), an output conductance of 0.334 (0.352) mS mm(-1), a gate-voltage swing (GVS) of 1.45 (1.5) V, a voltage gain (A(v)) of 505 (658) and a reverse breakdown voltage (BVGD) of -24.1 (-31.2) V at 500 (300) K, respectively, with gate dimensions of 0.65 x 200 mu m(2). In addition, the device demonstrates a superior stable thermal threshold coefficient (delta V-th/delta T) of -0.55 mV K-1, a thermal GVS coefficient (delta GVS/delta T) of -0.25 mV K-1 and a wide gate- bias range of 1.25 V for a unity-gain cut-off frequency (f(t)) of over 20 GHz. Consequently, the proposed device shows good potential for high-temperature and high- linearity circuit applications.