Performance of InGaP/InGaAs/GaAs camel-gate single δ-doping pHEMT

A newly designed single delta-doped InGaP/InGaAs/GaAs pseudomorphic HEMT with n⁺-GaAs/p⁺-InGaP/n-InGaP camel gate structure has been first fabricated and demonstrated. For a 1×100 μm² device, the experimental results show an extrinsic transconductance of 85 mS/mm and a saturation current density of 425 mA/mm. Significantly, due to the p-n depletion from p⁺-InGaP gate to channel region and the presence of ΔEc at InGaP/InGaAs heterostructure, the turn-on voltage of gate is larger than 1.7 V. In addition, an extremely broad gate voltage swing larger than 3 V with above 80% maximum g_m is obtained. The unit current cutoff frequency f_T and maximum oscillation frequency f_max are up to 18 and 30 GHz, respectively.