5 years ago

Low-Temperature Atomic Layer Deposition of Low-Resistivity Copper Thin Films Using Cu(dmap)2 and Tertiary Butyl Hydrazine

Low-Temperature Atomic Layer Deposition of Low-Resistivity Copper Thin Films Using Cu(dmap)2 and Tertiary Butyl Hydrazine
Markku Leskelä, Mikko Ritala, Daniel Peeters, Anjana Devi, Kenichiro Mizohata, Jyrki Räisänen, Katja Väyrynen
Herein, we describe a process for the low-temperature atomic layer deposition of copper using Cu(dmap)2 (dmap = dimethylamino-2-propoxide). The use of tertiary butyl hydrazine (TBH) as the reducing agent was found to have a significant improvement on the purity and the resistivity of the Cu films compared to previous processes. Our process was studied at low temperatures of 80–140 °C on native oxide terminated Si. At 120 °C, self-limiting Cu deposition was demonstrated with respect to both Cu(dmap)2 and TBH pulse lengths. During the initial stages of the deposition (125–1000 cycles), a growth rate of 0.17 Å/cycle was measured. Once the substrate surface was completely covered, deposition proceeded with a more moderate growth rate of 0.05 Å/cycle. According to X-ray diffraction, the films were crystalline cubic Cu with a slight preference toward (111) orientation. Based on scanning electron micrographs, the Cu films were relatively smooth with the roughness increasing as a function of both increasing temperature and thickness. A 54 nm film deposited at the low temperature of 120 °C exhibited a low resistivity of 1.9 μΩ·cm. Composition analysis on this film showed a remarkably high purity of approximately 99.4 at.%, with the rest being hydrogen and oxygen. The films could be deposited also on hydrogen terminated Si, glass, Al2O3, TiN, and Ru, extending the suitability of the process to a wide range of applications.

Publisher URL: http://dx.doi.org/10.1021/acs.chemmater.7b02098

DOI: 10.1021/acs.chemmater.7b02098

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.