Atomic Layer Deposition of Ruthenium and Ruthenium Oxide Thin Films from a Zero-Valent (1,5-Hexadiene)(1-isopropyl-4-methylbenzene)ruthenium Complex and O2

Abstract

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 O2 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 O2 feeding time. Metallic Ru films were deposited at growth temperatures of 230–350 °C, while the temperature window for the growth of the RuO2 film was limited to <230 °C. At 270 °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 O2. The resistivity of the Ru film was as low as 29–36 μΩ·cm at growth temperatures of 270–350 °C. On the other hand, the RuO2 film was grown at a low temperature of 200 °C and showed a GPC of 0.15 nm/cycle with a resistivity of ∼270 μΩ·cm. In situ quad...