Enhancement-mode buried gate InGaP/AlGaAs/InGaAs heterojunction FETs fabricated by selective wet etching

Enhancement-mode buried gate InGaP/AlGaAs/InGaAs heterojunction FETs (HJFETs) were successfully fabricated by using a highly-selective wet recess etching technique. The fabricated HJFET exhibited a maximum drain current of 202 mA/mm, a peak transconductance of 330mS/mm and a gate-drain breakdown voltage of 33V. Standard deviation of the threshold voltage was 60mV, which is less than one fifth that of the conventional AlGaAs/InGaAs HJFET. No appreciable frequency dispersion in the drain current was measured, indicating that the developed InGaP/AlGaAs/InGaAs HJFET with a buried gate structure is promising for large-signal microwave power applications.