0.1 μm (Al_0.5Ga_0.5)_0.5In_0.5P/In _0.2Ga_0.8As/GaAs PHEMT grown by gas source molecular beam epitaxy

We have successfully realised a 0.1 μm T-gate pseudomorphic (Al _0.5Ca_0.5)_0.5In_0.5P/In _0.2Ga_0.8As/GaAs high electron mobility transistor (PM-HEMT) grown on a GaAs substrate by gas source molecular beam epitaxy (GSMBE). The electronic transfer and mobility of the (Al_xGa _1-x)_0.5In_0.5P/In_0.2Ga _0.8As structure as functions of the aluminium composition have been studied. The ohmic contact has also been optimised. For a single-side doped structure, the devices exhibit the best RF and DC performances of the AlGaInP/InGaAs system with a current density of 430 mA/ mm and an extrinsic transconductance Gm of 550 mS/mm. The cutoff frequencies have been determined to be Ft=100 GHz and Fmax=160 GHz at Vds=1.5 V. These excellent performances clearly show the high-quality material grown by GSMBE