The 2DEG mobility enhancement for low- and high-electric fields in a new type of AlGaAs/InGaAs heterostructures with donor-acceptor doping

The splitting of the delta-layers in the DA-pHEMT heterostructures has resulted in the increase of the spacer's effective thickness and growth of the low-field 2DEG mobility from 4000÷5000 cm² V^-1 s^-1 up to 6500 cm² V^-1 s^-1 at the temperature of 300 K and 2DEG density of 4.0×10¹² cm^-2. The 2DEG mobility in the δ-splitted DA-pHEMT heterostructures almost coincides with the mobility in standard pHEMT heterostructures, but the 2DEG density in the DA-pHEMT heterostructures is approximately twice higher. The additional potential barrier in the DA-pHEMT heterostructures formed by the acceptors causes the reduction of the real-space transfer effect. Therefore, the drift saturation velocity in these heterostructures is higher than the drift saturation velocity in standard pHEMT heterostructures.