Electrical properties of Pd-based ohmic contact to p-GaN

Abstract

We have investigated the ohmic contact formation mechanism of Pd-based ohmic contacts to Mg-doped p-GaN grown by metalorganic chemical-vapor deposition. To examine room-temperature ohmic behavior, various metal contact systems were deposited and currentvoltage measurements were carried out. In spite of the large theoretical Schottky barrier height between Pd and p-GaN, Pd-based contacts showed perfect ohmic characteristic even before annealing. According to the results of synchrotron x-ray radiation, the Pd ͑111͒ layer grew epitaxially on GaN ͑0001͒ surfaces with Pd͓110͔ ʈ GaN͓1120͔. The closed-packed atomic planes of the Pd film were quite well ordered in surface normal direction, as well as in the in-plane direction. The effective Schottky barrier height of Au/Pd/Mg/Pd/p-GaN was 0.47 eV, which was estimated by the Norde method. This discrepancy between the theoretical barrier height and the measured one may be due to the epitaxial growth of Pd contact metal.

Ferroelectric and optical properties of Ba0.8Sr0.2TiO3 thin film

“…However, SBT films have a low dielectric constant and high crystallization temperature ͑ϳ800°C͒. A variety of processing techniques have been tried out to produce these thin films, including rf sputtering, sol gel, metalorganic chemical vapor deposition ͑MOCVD͒, laser ablation, [6][7][8][9][10] etc. On the other hand, barium strontium titanate ͑BST͒ is currently one of the most interesting ferroelectric materials due to its high dielectric constant and composition-dependent Curie temperature.…”

Contact mechanisms and design principles for alloyed ohmic contacts to n-GaN

“…As a result, thermionic emission can be a dominant mechanism for yielding low contact resistivity. An earlier investigation 36 could not explain the cause of low contact resistivity on the basis of tunneling. The present one appears to provide a convincing answer for this.…”

Room temperature deposition of crystalline indium tin oxide films by cesium-assisted magnetron sputtering

“…The direct ion deposition process has been proven to be very effective in the synthesis of thin films with high quality at low temperature because it can control the energy of deposited atoms [8][9][10]. Cesium-assisted sputtering is the one of direct ion deposition techniques leading to negative ionization of deposited atoms.…”