Fabrication of ultra-narrow channel InP-HEMTs with high density, uniformity and controllability

We succeed in fabricating ultra-narrow channel InGaAs/InAlAs HEMTs with high density (up to 8.3 × 10⁴ channels/cm), uniformity and controllability by using electron-beam (EB) lithography and wet chemical etching. Electrons are confined in the narrow channels formed by using a depletion layer underneath a corrugated gate electrode. 100-nm-gate HEMTs with sub-50-nm-wide channels show good I_ds-V_ds characteristics and superior charge controllability by a two-dimensional channel squeezing effect. At low temperatures, the HEMTs exhibit clear negative differential resistance (NDR) and conductance oscillations, which are indicative of one-dimensional nature of the fabricated ultra-narrow channels.