Effects of a High-k Dielectric on the Performance of III–V Ballistic Deflection Transistors

This letter presents a first successful integration of a high-k dielectric, i.e., Al₂O₃, with III-V semiconductors in ballistic deflection transistors (BDTs). The Al₂O₃ is deposited using atomic layer deposition, which allows the formation of uniform layers along the walls of etched trenches. The BDT transfer characteristic shows strong dependence on the dielectric permittivity of the material filling the etched trenches. When Al₂O₃ is deposited in the trenches, the transconductance of the BDT is enhanced and shifted to lower gate bias. Moreover, the ratio between output and leakage currents was also enhanced.