Study of Cu-growth feature by selective low-pressure chemical vapor deposition using a CuI precursor

• Published in: Japanese Journal of Applied Physics Vol. 62; no. SH; p. SH1002
• Main Authors: Toyoda, Gento, Kikuchi, Hikari, Yamauchi, Satoshi, Joutsuka, Tatsuya, Fuse, Takashi, Kubota, Yusuke
• Format: Journal Article
• Language: English
• Published: Tokyo IOP Publishing 01.07.2023; Japanese Journal of Applied Physics
• Subjects: Activation energy; Chemical vapor deposition; Copper; copper-iodide; Cu growth; Cuprous iodide; Desorption; Island growth; Low pressure; Nucleation; Precursors; selective chemical vapor deposition; ULSI metallization
• ISSN: 0021-4922; 1347-4065
• DOI: 10.35848/1347-4065/acc257

Abstract In this study, Cu-growth features are investigated using selective low-pressure CVD of Cu on Ru(001) using a copper(I) iodide precursor. While discrete columnar grains are formed below 320 °C, lateral Cu islands are grown above 380 °C. The CuI dissociation efficiency, which depends on the growth temperature, indicates two activation energies corresponding to I 2 desorption from Cu and Ru. The activation energy below 320 °C and above 380 °C are identified as the energies required for the desorption of I 2 from Cu(111) and Ru(001), respectively. At 400 °C, nucleation occurs at the initial stage, followed by the lateral growth of Cu-islands. A proposed growth model, involving dissociated Cu-atom contributions toward increasing the Cu-island height and Cu coverage on Ru, can explain the island growth features dependent on the growth time. Further, the growth model reveals an important factor to achieve thinner Cu layers growth entirely covering Ru.