One- and Zero-Dimensional Tunneling Diodes Fabricated by Focused Ion Beam Implantation

Summary

One-dimensional and zero-dimensional tunneling diodes were fabricated using focused Ga ion beam implantation. The current vs voltage (I-V) curves of one-dimensional diodes showed broad steps near the onset of the tunneling current, followed by a series of small current peaks at higher voltages. The I–V curves of the zero-dimensional diodes, however, showed a series of peaks at the onset of the tunneling current. These differences are well reproduced by calculating the tunneling of a three-dimensional electron through the one-dimensional or zero-dimensional well levels. In the zero-dimensional diode, the amplitude difference between neighboring current peaks was constant because of the degeneracy of the zero-dimensional well levels confined by a harmonic lateral potential. One-dimensional diodes with strong lateral confinement in the contact region were fabricated by implanting a low dose of ions. This tunneling current is generated by the mixing of one-dimensional (emitter) and two-dimensional (well) subbands whose eigenfunctions have the same parity.