Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O-2

초록

Ruthenium (Ru) and ruthenium oxide (RuO2) thin films were grown by atomic layer deposition (ALD) using a novel zerovalent (1,5-hexadiene)(1-isopropyl-4-methylbenzene)Ru complex and O-2 as the Ru precursor and oxidant, respectively. The self-limiting growth mode for the Ru and RuO2 ALD processes was achieved while varying the Ru precursor and O-2 feeding time. Metallic Ru films were deposited at growth temperatures of 230-350 degrees C, while the temperature window for the growth of the RuO2 film was limited to <230 degrees C. At 270 degrees C, the growth per cycle (GPC) of Ru ALD was 0.076 nm/cycle, and the incubation times of Ru on SiO2 and TiN substrates were considerably short (3 cycles on SiO2, negligible on TiN) compared to that of Ru ALD from a high-valent Ru precursor and O-2. The resistivity of the Ru film was as low as 29-36 mu O.cm at growth temperatures of 270-350 degrees C. On the other hand, the RuO2 film was grown at a low temperature of 200 degrees C and showed a GPC of 0.15 nm/cycle with a resistivity of similar to 270 mu O.cm. In situ quadruple mass spectrometry analysis of the CO2 byproduct revealed that the amount of subsurface oxygen extracted during the Ru pulse half-cycle affected the resultant film phase, either Ru or RuO2, which was strongly influenced by the growth temperature.

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