LOW-TEMPERATURE DC CHARACTERISTICS OF S-DOPED AND SI-DOPED GA0.51IN0.49P/GAAS HIGH ELECTRON-MOBILITY TRANSISTORS GROWN BY METALORGANIC MOLECULAR-BEAM EPITAXY

Ga0.51In0.49P/GaAs high electron mobility transistors (HEMTs) grown by metalorganic molecular beam epitaxy have been fabricated for the first time. The typical transconductance (g(m)) of devices of 1.3-mu-m gate length at 300 K is 110 mS/mm and is independent of donor type. At 100 K the dc characteristics of Si-doped devices remain almost unchanged, while there is a decrease of 55% in g(m) and in the drain-source saturation current (I(dss)) of the S-doped devices. The degradation of the S-doped HEMTs is attributed to "DX-like" centers in the doped GaInP layer. All of the doped samples are characterized by a deep electron trap with an activation energy that takes values in the range 310-345 meV and causes persistent photoconductivity (PPC) in S-doped samples, while Si doping suppresses the PPC effect.