Submicrometer GaAs MESFET with shallow channel and very high transconductance

A 0.5-µm GaAs MESFET with a 25-nm thin channel, 400- mS/mm maximum transconductance, and 580-mS/V.mm K value is presented. This extremely high K value was obtained using an electron-beam fabricated recessed-gate MESFET structure on a highly doped (9.10¹⁷cm^-3) MBE-grown channel layer with 2600-cm²/V.s mobility. The use of thin channels and a buried p-layer also reduced the output conductance and other short-channel effects dramatically. As a result, these scaled MESFET's are very promising for high-speed digital logic circuits.