Formation of low resistance Ti/Al-based ohmic contacts on (11-22) semipolar n-type GaN

Jae Seong Park; Jaecheon Han; Tae Yeon Seong

doi:10.1016/j.jallcom.2015.08.181

Formation of low resistance Ti/Al-based ohmic contacts on (11-22) semipolar n-type GaN

Jae Seong Park, Jaecheon Han, Tae Yeon Seong

Research output: Contribution to journal › Article › peer-review

9 Citations (Scopus)

Abstract

The electrical properties of Ti/Al-based ohmic contacts to (0001) c-plane and (11-22) semipolar n-type GaN were investigated as a function of annealing temperature. The electrical properties of both c-plane Ti/Al/Au and semi-polar Ti/(Ta)/Al/Au contacts became improved upon annealing at 600 °C for 1 min. The specific contact resistances of the 600 °C-annealed c-plane Ti/Al/Au, semi-polar Ti/Al/Au, and semipolar Ti/Ta/Al/Au contacts were 3.2 × 10^-4, 1.5 × 10^-4, and 4.8 × 10^-5 Ωcm², respectively. The X-ray photoemission spectroscopy (XPS) results showed that the Ga 2p core level for the c-plane samples experienced a smaller shift toward the conduction band than that for the semipolar samples. The XPS depth profile results exhibited that the semipolar samples contained more interfacial oxygen than the c-plane samples. Oxygen was present in the form of Al-oxide at the interface region, but as oxygen atoms in the GaN surface region. On the basis of the electrical and XPS results, the annealing-induced improvement of the electrical properties was described in terms of the formation of donor-like defects.

Original language	English
Pages (from-to)	167-171
Number of pages	5
Journal	Journal of Alloys and Compounds
Volume	652
DOIs	https://doi.org/10.1016/j.jallcom.2015.08.181
Publication status	Published - 2015 Dec 15

Bibliographical note

Funding Information:
This work was supported by LG Innotek, Co., Ltd .

Publisher Copyright:
© 2015 Elsevier B.V. All rights reserved.

Keywords

Light-emitting diode
Ohmic contact
Semipolar GaN
Ti/Al

ASJC Scopus subject areas

Mechanics of Materials
Mechanical Engineering
Metals and Alloys
Materials Chemistry

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10.1016/j.jallcom.2015.08.181

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title = "Formation of low resistance Ti/Al-based ohmic contacts on (11-22) semipolar n-type GaN",

abstract = "The electrical properties of Ti/Al-based ohmic contacts to (0001) c-plane and (11-22) semipolar n-type GaN were investigated as a function of annealing temperature. The electrical properties of both c-plane Ti/Al/Au and semi-polar Ti/(Ta)/Al/Au contacts became improved upon annealing at 600 °C for 1 min. The specific contact resistances of the 600 °C-annealed c-plane Ti/Al/Au, semi-polar Ti/Al/Au, and semipolar Ti/Ta/Al/Au contacts were 3.2 × 10-4, 1.5 × 10-4, and 4.8 × 10-5 Ωcm2, respectively. The X-ray photoemission spectroscopy (XPS) results showed that the Ga 2p core level for the c-plane samples experienced a smaller shift toward the conduction band than that for the semipolar samples. The XPS depth profile results exhibited that the semipolar samples contained more interfacial oxygen than the c-plane samples. Oxygen was present in the form of Al-oxide at the interface region, but as oxygen atoms in the GaN surface region. On the basis of the electrical and XPS results, the annealing-induced improvement of the electrical properties was described in terms of the formation of donor-like defects.",

keywords = "Light-emitting diode, Ohmic contact, Semipolar GaN, Ti/Al",

author = "Park, {Jae Seong} and Jaecheon Han and Seong, {Tae Yeon}",

year = "2015",

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doi = "10.1016/j.jallcom.2015.08.181",

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T1 - Formation of low resistance Ti/Al-based ohmic contacts on (11-22) semipolar n-type GaN

AU - Park, Jae Seong

AU - Han, Jaecheon

AU - Seong, Tae Yeon

PY - 2015/12/15

Y1 - 2015/12/15

N2 - The electrical properties of Ti/Al-based ohmic contacts to (0001) c-plane and (11-22) semipolar n-type GaN were investigated as a function of annealing temperature. The electrical properties of both c-plane Ti/Al/Au and semi-polar Ti/(Ta)/Al/Au contacts became improved upon annealing at 600 °C for 1 min. The specific contact resistances of the 600 °C-annealed c-plane Ti/Al/Au, semi-polar Ti/Al/Au, and semipolar Ti/Ta/Al/Au contacts were 3.2 × 10-4, 1.5 × 10-4, and 4.8 × 10-5 Ωcm2, respectively. The X-ray photoemission spectroscopy (XPS) results showed that the Ga 2p core level for the c-plane samples experienced a smaller shift toward the conduction band than that for the semipolar samples. The XPS depth profile results exhibited that the semipolar samples contained more interfacial oxygen than the c-plane samples. Oxygen was present in the form of Al-oxide at the interface region, but as oxygen atoms in the GaN surface region. On the basis of the electrical and XPS results, the annealing-induced improvement of the electrical properties was described in terms of the formation of donor-like defects.

AB - The electrical properties of Ti/Al-based ohmic contacts to (0001) c-plane and (11-22) semipolar n-type GaN were investigated as a function of annealing temperature. The electrical properties of both c-plane Ti/Al/Au and semi-polar Ti/(Ta)/Al/Au contacts became improved upon annealing at 600 °C for 1 min. The specific contact resistances of the 600 °C-annealed c-plane Ti/Al/Au, semi-polar Ti/Al/Au, and semipolar Ti/Ta/Al/Au contacts were 3.2 × 10-4, 1.5 × 10-4, and 4.8 × 10-5 Ωcm2, respectively. The X-ray photoemission spectroscopy (XPS) results showed that the Ga 2p core level for the c-plane samples experienced a smaller shift toward the conduction band than that for the semipolar samples. The XPS depth profile results exhibited that the semipolar samples contained more interfacial oxygen than the c-plane samples. Oxygen was present in the form of Al-oxide at the interface region, but as oxygen atoms in the GaN surface region. On the basis of the electrical and XPS results, the annealing-induced improvement of the electrical properties was described in terms of the formation of donor-like defects.

KW - Light-emitting diode

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Formation of low resistance Ti/Al-based ohmic contacts on (11-22) semipolar n-type GaN

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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