Nanoscale Schottky contacts to GaN: Theoretical study and a brief review

Minority carrier effects in nanoscale Schottky contacts.

We report the current-voltage behavior for nanoscale point contacts to Si(111) obtained in ultrahigh vacuum using scanning tunneling microscopy. Epitaxial CoSi(2) islands provide single-crystal contacts with well-defined size and shape. The zero bias conductance is found to be independent of the island size (10(2)-10(4) nm(2)) and shape, but varies strongly with the surface Fermi level position...

Thermally stable Schottky contacts on n-type GaN using ZrB2

The electrical properties and thermal stability of ZrB2 Schottky contacts deposited on n-type GaN have been studied. As-deposited contacts had a barrier height of 0.80 eV, which decreased to 0.7 eV after annealing at 300 °C, and to 0.6 eV after additional annealing at 400 °C in nitrogen for 20 min. However, the barrier height remained at about 0.6 eV even when the diodes were annealed at 600 °C...

Analysis of leakage current mechanisms in Schottky contacts to GaN and Al0.25Ga0.75N/GaN grown by molecular-beam epitaxy

Temperature-dependent current-voltage measurements combined with conductive atomic force microscopy and analytical modeling have been used to assess possible mechanisms of reverse-bias leakage current flow in Schottky diodes fabricated from GaN and Al0.25Ga0.75N/GaN structures grown by molecular-beam epitaxy. Below 150 K, leakage current is nearly independent of temperature, indicating that con...

X-ray photoemission determination of the Schottky barrier height of metal contacts to n–GaN and p–GaN

Synchrotron radiation-based x-ray photoemission spectroscopy was used to study the surface Fermi level position within the band gap for thin metal overlayers of Au, Al, Ni, Ti, Pt, and Pd on n–GaN and p–GaN. Nonequilibrium effects were taken into account by measuring the Fermi edge of the metal overlayer. There are two different behaviors observed for the six metals studied. For Au, Ti, and Pt,...

Nanopatterned contacts to GaN