Characterization of Three-Terminal, Junctions Operated as In-Plane Gated Field-Effect Transistors

The field-effect transistor operation of monolithic three-terminal junctions (TTJs) is demonstrated at room temperature. The TTJs are based on a modulation-doped GaAs/AlGaAs heterostructure with a 2-D electron gas situated 33 nm below the surface. By applying mask technology and wet chemical etching, several TTJs were fabricated, and the interplay between the TTJ geometry and the transistor characteristics is analyzed. For channel width smaller than 200 nm, drain currents of up to 9.3 mu A and a maximum transconductance exceeding 15.7 mu A/V are observed in the transfer characteristics. It is also demonstrated that engineering the channel and gate branch allows one to control the device currents and the threshold voltages over a wide range.