The pHEMT heterostructures optimized in this work to improve the parameters of switching microwave transistors have a one-sided delta-doping at 6· 1012 cm-2 and an AlAs/GaAs spacer. Such heterostructures were used to fabricate the monolithic integrated circuits of single-pole double throw pHEMT switches with gate length and width of 0.5 μm and 100 μm, respectively. The resulting transistors had the following parameters: gmax=400 mS/mm, saturation current ID=380 mA/mm, ON-state resistance 1.0 Ω· mm, OFF-state capacitance 0.37 pF/mm. The switch parameters at 20 GHz are: insertion loss -2.2 dB, isolation -56 dB, return loss -11.7 dB, linearity P1 dB=21 dBm and IIP3=40 dBm. Keywords: Single-side doping, spacer design, maximal conductivity, pHEMT, switches.
The internal quantum efficiency of GaAs/AlGaAs- and InGaAs/AlGaAs-heterostructures for infrared light emitter diodes has been determined. The influence of the growth conditions of heterostructures grown by the molecular beam epitaxy and post-growth annealing on the quantum efficiency of heterostructures has been investigated. It has been shown that it is possible to increase the quantum luminescence efficiency of the studied heterostructures up to 75-80% at the average power by the combined optimization of these processes. Keywords: GaAs/AlGaAs and InGaAs/AlGaAs heterostructures, internal quantum exit, photoluminescence, molecular-beam epitaxy.
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