A Novel GaAs/InGaAs/AlGaAs Structure of Modulation-Doped Field-Effect Transistors with High Transconductances

Novel structure GaAs/InGaAs/AlGaAs pseudomorphic modulation-doped field-effect transistors (MODFETs) with a buried p-i-n dipole layer and a 200 nm buffer layer have been fabricated. According to the calculation, the dipole buried layer not only results in the very thin buffer layer required, but also enhances the density of two-dimensional electron gas. The measured transconductances of these MODFETs, with a gate length of 2 μm and a drain-source spacing of 5 μm, are as high as 320 mS/mm and the measured maximum drain currents of the typical devices are higher than 500 mA/mm.