On the importance of Ni-Au-Ga interdiffusion in the formation of a Ni-Au / p-GaN ohmic contact

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Main Authors: Duraz, Jules, Souissi, Hassen, Gromovyi, Maksym, Troadec, David, Baptiste, Teo, Findling, Nathaniel, Vuong, Phuong, Gujrati, Rajat, Tran, Thi May, Salvestrini, Jean Paul, Tchernycheva, Maria, Sundaram, Suresh, Ougazzaden, Abdallah, Patriarche, Gilles, Bouchoule, Sophie
Format: Preprint
Published: 2024
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author Duraz, Jules
Souissi, Hassen
Gromovyi, Maksym
Troadec, David
Baptiste, Teo
Findling, Nathaniel
Vuong, Phuong
Gujrati, Rajat
Tran, Thi May
Salvestrini, Jean Paul
Tchernycheva, Maria
Sundaram, Suresh
Ougazzaden, Abdallah
Patriarche, Gilles
Bouchoule, Sophie
author_facet Duraz, Jules
Souissi, Hassen
Gromovyi, Maksym
Troadec, David
Baptiste, Teo
Findling, Nathaniel
Vuong, Phuong
Gujrati, Rajat
Tran, Thi May
Salvestrini, Jean Paul
Tchernycheva, Maria
Sundaram, Suresh
Ougazzaden, Abdallah
Patriarche, Gilles
Bouchoule, Sophie
contents The Ni-Au-Ga interdiffusion mechanisms taking place during rapid thermal annealing (RTA) under oxygen atmosphere of a Ni-Au/p-GaN contact are investigated by high-resolution transmission electron microscopy (HR-TEM) coupled to energy dispersive X-ray spectroscopy (EDX). It is shown that oxygen-assisted, Ni diffusion to the top surface of the metallic contact through the formation of a nickel oxide (NiOx) is accompanied by Au diffusion down to the GaN surface, and by Ga out-diffusion through the GaN/metal interface. Electrical characterizations of the contact by Transmission Line Method (TLM) show that an ohmic contact is obtained as soon as a thin, Au-Ga interfacial layer is formed, even after complete diffusion of Ni or NiOx to the top surface of the contact. Our results clarify that the presence of Ni or NiOx at the interface is not the main origin of the ohmic-like behavior in such contacts. Auto-cleaning of the interface during the interdiffusion process may play a role, but TEM-EDX analysis evidences that the creation of Ga vacancies associated to the formation of a Ga-Au interfacial layer is crucial for reducing the Schottky barrier height, and maximizing the amount of current flowing through the contact.
format Preprint
id arxiv_https___arxiv_org_abs_2412_11887
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the importance of Ni-Au-Ga interdiffusion in the formation of a Ni-Au / p-GaN ohmic contact
Duraz, Jules
Souissi, Hassen
Gromovyi, Maksym
Troadec, David
Baptiste, Teo
Findling, Nathaniel
Vuong, Phuong
Gujrati, Rajat
Tran, Thi May
Salvestrini, Jean Paul
Tchernycheva, Maria
Sundaram, Suresh
Ougazzaden, Abdallah
Patriarche, Gilles
Bouchoule, Sophie
Materials Science
Applied Physics
The Ni-Au-Ga interdiffusion mechanisms taking place during rapid thermal annealing (RTA) under oxygen atmosphere of a Ni-Au/p-GaN contact are investigated by high-resolution transmission electron microscopy (HR-TEM) coupled to energy dispersive X-ray spectroscopy (EDX). It is shown that oxygen-assisted, Ni diffusion to the top surface of the metallic contact through the formation of a nickel oxide (NiOx) is accompanied by Au diffusion down to the GaN surface, and by Ga out-diffusion through the GaN/metal interface. Electrical characterizations of the contact by Transmission Line Method (TLM) show that an ohmic contact is obtained as soon as a thin, Au-Ga interfacial layer is formed, even after complete diffusion of Ni or NiOx to the top surface of the contact. Our results clarify that the presence of Ni or NiOx at the interface is not the main origin of the ohmic-like behavior in such contacts. Auto-cleaning of the interface during the interdiffusion process may play a role, but TEM-EDX analysis evidences that the creation of Ga vacancies associated to the formation of a Ga-Au interfacial layer is crucial for reducing the Schottky barrier height, and maximizing the amount of current flowing through the contact.
title On the importance of Ni-Au-Ga interdiffusion in the formation of a Ni-Au / p-GaN ohmic contact
topic Materials Science
Applied Physics
url https://arxiv.org/abs/2412.11887