Low temperature atomic layer deposition of cobalt using dicobalt hexacarbonyl-1-heptyne as precursor

Mathias Franz; Mahnaz Safian Jouzdani; Lysann Kaßner; Marcus Daniel; Frank Stahr; Stefan E Schulz

doi:10.3762/bjnano.14.78

Low temperature atomic layer deposition of cobalt using dicobalt hexacarbonyl-1-heptyne as precursor

Beilstein J Nanotechnol. 2023 Sep 15:14:951-963. doi: 10.3762/bjnano.14.78. eCollection 2023.

Authors

Mathias Franz¹, Mahnaz Safian Jouzdani², Lysann Kaßner¹, Marcus Daniel³, Frank Stahr⁴, Stefan E Schulz^{1

2}

Affiliations

¹ Fraunhofer-Institute for Electronic Nano Systems ENAS, Technologie-Campus 3, 09126 Chemnitz, Germany.
² Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
³ scia Systems GmbH, Clemens-Winkler-Str. 6c, 09116 Chemnitz, Germany.
⁴ FAP Forschungs- und Applikationslabor Plasmatechnik GmbH, Gostritzer Str. 67B, 01217 Dresden, Germany.

Abstract

In this work, we present the development of an atomic layer deposition (ALD) process for metallic cobalt. The process operates at low temperatures using dicobalt hexacarbonyl-1-heptyne [Co₂(CO)₆HC≡CC₅H₁₁] and hydrogen plasma. For this precursor an ALD window in the temperature range between 50 and 110 °C was determined with a constant deposition rate of approximately 0.1 Å/cycle. The upper limit of the ALD window is defined by the onset of the decomposition of the precursor. In our case, decomposition occurs at temperatures of 125 °C and above, resulting in a film growth in chemical vapour deposition mode. The lower limit of the ALD window is around 35 °C, where the reduction of the precursor is incomplete. The saturation behaviour of the process was investigated. X-ray photoelectron spectroscopy measurements could show that the deposited cobalt is in the metallic state. The finally established process in ALD mode shows a homogeneous coating at the wafer level.

Keywords: PEALD; XPS; atomic layer deposition (ALD); cobalt; low-temperature ALD; plasma-enhanced ALD.

Grants and funding

This work was funded by the EFRE fund of the European Commission and by funding of the Free State of Saxony of the Federal Republic of Germany (project ALMET, grant number 100302427).