Model and analysis of a delta-doping field-effect transistors utilizing an InGaP/GaAs camel-gate structure

In this paper, the performances of a new δ-doping field-effect transistor utilizing an InGaP/GaAs camel-gate structure by theoretical and experimental analysis will be reported. An analytical model related to drain saturation current, transconductance, potential barrier height, gate-to-source depletion capacitance, and unit current gain frequency is developed to explain the device performances. The employments of n⁺-GaAs/p⁺-InGaP/n-GaAs heterostructure gate and the δ-doping channel with heavy-doping level were used to improve transconductance linearity and enhance current drivability. For a 1×100 μm² device, the experimental results show that a drain saturation current of 1120 mA/mm, a maximum transconductance of 240 mS/mm, and a large V_gs swing larger than 3.5 V with the transconductance higher than 200 mS/mm are obtained. In addition, the measured unit current gain frequency f_t is 22 GHz. These experimental results are consistent with theoretical analysis.