Low resistance Al/Ti/n-GaN ohmic contacts with improved surface morphology and thermal stability

Joon Seop Kwak, Suzanne E. Mohney, Je Yi Lin, Rs Kern

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

The Al/Ti/n-GaN ohmic contact and multilayer variations on this contact are widely used because of the low contact resistivities they provide to n-GaN. However, there are few reports that reveal the influence of the atomic ratio of Al to Ti on the contact resistivity, thermal stability and surface morphology of the contacts. This study reveals that the ratio of Al to Ti strongly influences all of these characteristics. All contacts in this study had atomic ratios of Al to Ti higher than 1. Those contacts with ratios, of Al to Ti less than 3 required higher annealing temperatures or longer annealing times to reach comparable contact resistivities compared to the more Al-rich contacts. On the other hand, the less Al-rich contacts provided several advantages. They exhibited smooth surface morphologies even after they were annealed at temperatures near 1000 °C, and they suffered much less severe degradation during long-term aging at 600 °C. These findings are explained by differences in the phases formed after annealing.

Original languageEnglish (US)
Pages (from-to)756-760
Number of pages5
JournalSemiconductor Science and Technology
Volume15
Issue number7
DOIs
StatePublished - Jul 1 2000

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Ohmic contacts
low resistance
Surface morphology
electric contacts
Thermodynamic stability
thermal stability
Annealing
electrical resistivity
annealing
Multilayers
Aging of materials
Degradation
Temperature
degradation
temperature

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

Cite this

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abstract = "The Al/Ti/n-GaN ohmic contact and multilayer variations on this contact are widely used because of the low contact resistivities they provide to n-GaN. However, there are few reports that reveal the influence of the atomic ratio of Al to Ti on the contact resistivity, thermal stability and surface morphology of the contacts. This study reveals that the ratio of Al to Ti strongly influences all of these characteristics. All contacts in this study had atomic ratios of Al to Ti higher than 1. Those contacts with ratios, of Al to Ti less than 3 required higher annealing temperatures or longer annealing times to reach comparable contact resistivities compared to the more Al-rich contacts. On the other hand, the less Al-rich contacts provided several advantages. They exhibited smooth surface morphologies even after they were annealed at temperatures near 1000 °C, and they suffered much less severe degradation during long-term aging at 600 °C. These findings are explained by differences in the phases formed after annealing.",
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Low resistance Al/Ti/n-GaN ohmic contacts with improved surface morphology and thermal stability. / Kwak, Joon Seop; Mohney, Suzanne E.; Lin, Je Yi; Kern, Rs.

In: Semiconductor Science and Technology, Vol. 15, No. 7, 01.07.2000, p. 756-760.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Low resistance Al/Ti/n-GaN ohmic contacts with improved surface morphology and thermal stability

AU - Kwak, Joon Seop

AU - Mohney, Suzanne E.

AU - Lin, Je Yi

AU - Kern, Rs

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Y1 - 2000/7/1

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AB - The Al/Ti/n-GaN ohmic contact and multilayer variations on this contact are widely used because of the low contact resistivities they provide to n-GaN. However, there are few reports that reveal the influence of the atomic ratio of Al to Ti on the contact resistivity, thermal stability and surface morphology of the contacts. This study reveals that the ratio of Al to Ti strongly influences all of these characteristics. All contacts in this study had atomic ratios of Al to Ti higher than 1. Those contacts with ratios, of Al to Ti less than 3 required higher annealing temperatures or longer annealing times to reach comparable contact resistivities compared to the more Al-rich contacts. On the other hand, the less Al-rich contacts provided several advantages. They exhibited smooth surface morphologies even after they were annealed at temperatures near 1000 °C, and they suffered much less severe degradation during long-term aging at 600 °C. These findings are explained by differences in the phases formed after annealing.

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