Fabrication and Performance of 0.25-$mu$m Gate Length Depletion-Mode GaAs-Channel MOSFETs With Self-Aligned InAlP Native Oxide Gate Dielectric

摘要

The fabrication and performance of 0.25-$mu$m gate length GaAs-channel MOSFETs using the wet thermal native oxide of InAlP as the gate dielectric are reported. A fabrication process that self-aligns the gate oxidation to the gate recess and metallization to reduce the source access resistance is demonstrated for the first time. The fabricated devices exhibit a peak extrinsic transconductance of 144 mS/mm, an on-resistance of 3.46 $Omega$-mm, and a threshold voltage of $-1.8$ V for typical 0.25- $mu$m gate devices. A record cutoff frequency $f_t$ of 31 GHz for a GaAs-channel MOSFET and a maximum frequency of oscillation $f_{{bf max}}$ of 47 GHz have also been measured.