0.1-MU M-GATE METAMORPHIC HIGH-ELECTRON-MOBILITY TRANSISTOR ON GaAs AND ITS APPLICATION TO SOURCE-COUPLED FIELD-EFFECT TRANSISTOR LOGIC

The device performances of 0.1-mu m-gate InxGa1-xAs/InyAl1-yAs metamorphic high-electron-mobility transistors (MM-HEMTs) on GaAs substrates, depending on the In composition (XIn), have been investigated. By reducing the XIn, the gate-to-drain breakdown voltage (BVgd) of the MM-HEMT can be improved, while the transconductance (gm) and the current gain cut-off frequency (fT) decrease because of a reduction in electron mobility of the InxGa1-xAs channel. The balanced values of gm of 900 mS/mm, fT of 166 GHz and BVgd of 5.2 V for the MM-HEMT with XIn of 0.45 have been obtained. The propagation delay of a source-coupled field-effect transistor logic inverter implemented by MM-HEMTs rapidly increases with decreasing XIn, due to the increase in series resistance of the Schottky diode in the source-follower circuit. 15 refs.