Fabrication of diamond/Cu direct bonding interface for power device applications

Shinji Kanda, Yasuo Shimizu, Yutaka Ohno, Kenji Shirasaki, Yasuyoshi Nagai, Makoto Kasu, Naoteru Shigekawa, Jianbo Liang

Research output: Contribution to journalArticle

Abstract

Direct bonding of diamond and Cu was successfully conducted by the surface activated bonding method at room temperature. The structure of the diamond/Cu bonding interface was investigated by transmission electron microscopy and electron energy-loss spectroscopy. The effect of heat treatment temperature on the interface structure was also investigated. A 4-nm-thick damaged layer was formed at the as-bonded interface, and the damaged layer's thickness decreased with an annealing temperature rise. It was found that the atomic ratio of sp2 bonding in the bonding interface was larger than that of the diamond separated from the interface by approximately 50 nm, which indicates that the damaged layer was composed of amorphous carbon or graphite and diamond. After annealing at 700 °C, a composite layer about 2 nm thick was observed at the interface. There were no nano-voids or micro-cracks observed at the interface with annealing at a temperature as high as 700 °C. These results indicate that the diamond/Cu bonding interface has high thermal stability and can withstand the temperature rise of power devices during operation.

Original languageEnglish
Article numberSBBB03
JournalJapanese journal of applied physics
Volume59
Issue numberSB
DOIs
Publication statusPublished - 2020 Feb 1

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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