Channel-length effects in quarter-micrometer gate-length GaAs MESFET's

The electrical performance of 0.25-micron gate-length GaAs MESFETs with channel lengths (i.e., source-drain spacings) of 2.1 and 0.5 microns is compared. An extremely short channel length has been found experimentally to lead to significant increases in the electron average drift velocity, transconductance, and forward transducer gain. Increases in both the electron average drift velocity and intrinsic dc transconductance of about 70 percent were observed in these 0.25-micron gate-length devices when the source-drain spacing was reduced from 2.1 to 0.5 micron. Deleterious effects, such as increased output conductance and interelectrode capacitances, were also noted.