LOW DOPED P-TYPE ALGAAS BUFFER LAYERS GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION USING INTRINSIC CARBON DOPING METHOD

Low-doped (similar to 10(16) cm(-3)) and low-compensated p-type AlGaAs layers grown by metalorganic chemical vapor deposition (MOCVD) were s tudied to determine the optimal growth conditions for p-type buffer la yers in GaAs field-effect transistors (FETs). Good reproducibility of doping control was confirmed with the use of an intrinsic carbon dopin g method. As the growth conditions were varied, significant changes in the compensation ratio of-type AlGaAs layers were observed. While the Al0.15Ga0.85As layer with a compensation ratio of 0.4 exhibited a hol e mobility of 142 cm(2)/V.s, a larger hole mobility of 170 cm(2)/V.s w as obtained for the sample with a compensation ratio of 0.1. The growt h condition of high V/III ratio and a low growth temperature are prefe rable for the growth of low-doped and low-compensated p-type AlGaAs bu ffer layer.