Low-temperature dc characteristics of S- and Si-doped Ga0.51In0.49P/GaAs high electron mobility transistors grown by metalorganic molecular beam epitaxy

Abstract

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 (gm) of devices of 1.3-μm 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 gm and in the drain-source saturation current (Idss) 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.