Doped channel pseudomorphic GaAs/InGaAs/AlGaAs hetero-structure FETs

We report experimental and theoretical results obtained for pseudomorphic InGaAs Doped Channel Heterostructure FETs (DCHFET) that demonstrate the advantages of this device over other heterostructure FETs. We demonstrate high transconductance beta value, and saturation current and low output conductance and subthreshold current. These improvements are due to a higher density of carriers in the channel, the carrier confinement in the quantum well device structure, and the superior transport properties of InGaAs. Transconductances of 350 mS/mm and beta-values of 440 mS/V-mm were measured for 1-µm enhancement mode DCHFETs. Transconductances as high as 471 mS/mm and drain saturation currents as high as 660 mA/mm were measured for 0.6 µm depletion mode DCHFETs.