<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">Electrical characteristics and elemental depth profiles of ohmic contacts to p-GaN using Au/Ni-Mg-O<italic>x</italic> metallization have been investigated. The objective was to examine the possibilities of increasing the charge carrier concentration in the surface region of GaN by adding Mg, thus of a p-type dopant into the Au/NiO<italic>x</italic> metallization structure. For this purpose, a Ni-Mg-O<italic>x</italic> layer with a low concentration of Mg was deposited on p-GaN by dc reactive magnetron sputtering. The top Au layer was deposited in a similar way. The fabricated contact structures were annealed in N2. When the Ni-Mg layer in the Au/Ni-Mg-O<italic>x</italic>/p-GaN structure was deposited in an atmosphere with a low concentration of oxygen (0.2 at%), the structure exhibited a low resistance ohmic nature. The contact resistance was lower than in the case of a Au/Ni-O<italic>x</italic>/p-GaN structure without the Mg dopant in the metallic layer. An increase in the concentration of oxygen in the working atmosphere resulted in higher values of the contact resistance of the Au/Ni-Mg-O<italic>x</italic>/p-GaN structure. In our opinion the ohmic nature of the contact structure is related to the existence of a metal/p-NiO/p-GaN scheme. The measured values of the contact resistance in the Au/Ni-Mg-O<italic>x</italic>/p-GaN structure in comparison with the Au/Ni-O<italic>x</italic>/p-GaN structure are caused by an increased charge carrier concentration in the surface region of p-GaN, which is a consequence of Mg diffusion from the Ni-Mg-O<italic>x</italic> layer.</abstract>

Electrical characteristics and elemental depth profiles of ohmic contacts to p-GaN using Au/Ni-Mg-Ox metallization have been investigated. The objective was to examine the possibilities of increasing the charge carrier concentration in the surface region of GaN by adding Mg, thus of a p-type dopant into the Au/NiOx metallization structure. For this purpose, a Ni-Mg-Ox layer with a low concentration of Mg was deposited on p-GaN by dc reactive magnetron sputtering. The top Au layer was deposited in a similar way. The fabricated contact structures were annealed in N2. When the Ni-Mg layer in the Au/Ni-Mg-Ox/p-GaN structure was deposited in an atmosphere with a low concentration of oxygen (0.2 at%), the structure exhibited a low resistance ohmic nature. The contact resistance was lower than in the case of a Au/Ni-Ox/p-GaN structure without the Mg dopant in the metallic layer. An increase in the concentration of oxygen in the working atmosphere resulted in higher values of the contact resistance of the Au/Ni-Mg-Ox/p-GaN structure. In our opinion the ohmic nature of the contact structure is related to the existence of a metal/p-NiO/p-GaN scheme. The measured values of the contact resistance in the Au/Ni-Mg-Ox/p-GaN structure in comparison with the Au/Ni-Ox/p-GaN structure are caused by an increased charge carrier concentration in the surface region of p-GaN, which is a consequence of Mg diffusion from the Ni-Mg-Ox layer.

Ohmic contacts to p-GaN Using Au/Ni-Mg-O Metallization

Department of Microelectronics, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava, Slovakia

Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstr. 69, A-4040 Linz, Austria

Institute of Electrical Engineering, Slovak Academy of Sciences, Dúbravská cesta 9,841 04 Bratislava, Slovakia

Center of Micro- and Nanotechnologies, Technical University of Ilmenau, Gustav Kirchhoffstr. 7, D-986 93 Ilmenau, Germany

Journal of Electrical Engineering

{"article-title":"Ohmic contacts to p-GaN Using Au/Ni-Mg-O Metallization"}

Electrical characteristics and elemental depth profiles of ohmic contacts to p-GaN using Au/Ni-Mg-Ox metallization have been investigated. The objective was to...

Ohmic contacts to p-GaN Using Au/Ni-Mg-O Metallization

Published Online: Jun 07, 2011

Page range: 378 - 381

DOI: https://doi.org/10.2478/v10187-010-0058-8

Keywords
p-GaN, Au/Ni-Mg-O/p-GaN contact structure, AES depth profiling, low resistance ohmic contact

This content is open access.

Ohmic contacts to p-GaN Using Au/Ni-Mg-O Metallization

Published Online: Jun 07, 2011

Page range: 378 - 381

DOI: https://doi.org/10.2478/v10187-010-0058-8

Keywordsp-GaN, Au/Ni-Mg-O/p-GaN contact structure, AES depth profiling, low resistance ohmic contact

This content is open access.

Keywords
p-GaN, Au/Ni-Mg-O/p-GaN contact structure, AES depth profiling, low resistance ohmic contact