Fabrication and Low Temperature Transport Studies of Sub-Micron, In-Plane Gated Fets Defined by Low Energy Ion Exposure

ABSTRACTNanoscale gated quantum wires in GaAs MODFET material with the conduction channel and gates in the plane of the 2DEG have been fabricated and studied. Electron beam lithography was used for mask definition followed by flood exposure to low energy argon ions (150 eV) for pattern transfer into the 2DEG. Compared to metal top-gate designs the in-plane design simplifies fabrication and reduces device capacitance, promising ultra-fast operation. This method of pattern transfer produced devices having channel-to-gate isolation of 1014 Ω and breakdown fields above 106 V/cm at 4.2 K. In addition to exhibiting standard FET characteristics, including gating to pinchoff, the devices showed significant negative differential resistance (NDR) in the saturation region.