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 2μm and a drain-source spacing of 5μm,are as high as 320mS/mm and the measured maximum drain currents of the typical devices are higher than 500mA/mm.