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 and Stefan E. Schulz

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.

Link zum Paper: https://doi.org/10.3762/bjnano.14.78