Ag films grown by remote plasma enhanced atomic layer deposition on different substrates

• Published in: Journal of vacuum science & technology. A, Vacuum, surfaces, and films Vacuum, surfaces, and films, 2016-01, Vol.34 (1)
• Main Authors: Amusan, Akinwumi A., Kalkofen, Bodo, Gargouri, Hassan, Wandel, Klaus, Pinnow, Cay, Lisker, Marco, Burte, Edmund P.
• Format: Article
• Language: English
• Subjects: ATOMIC FORCE MICROSCOPY; MATERIALS SCIENCE; SCANNING ELECTRON MICROSCOPY; SILICON OXIDES; SUBSTRATES; THIN FILMS; TITANIUM NITRIDES; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; X-RAY FLUORESCENCE ANALYSIS; X-RAY PHOTOELECTRON SPECTROSCOPY
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/1.4936221

Silver (Ag) layers were deposited by remote plasma enhanced atomic layer deposition (PALD) using Ag(fod)(PEt3) (fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluorooctane-3,5-dionato) as precursor and hydrogen plasma on silicon substrate covered with thin films of SiO2, TiN, Ti/TiN, Co, Ni, and W at different deposition temperatures from 70  to 200 °C. The deposited silver films were analyzed by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) with energy dispersive x-ray spectroscopy, four point probe measurement, ellipsometric measurement, x-ray fluorescence (XRF), and x-ray diffraction (XRD). XPS revealed pure Ag with carbon and oxygen contamination close to the detection limit after 30 s argon sputtering for depositions made at 120 and 200 °C substrate temperatures. However, an oxygen contamination was detected in the Ag film deposited at 70 °C after 12 s argon sputtering. A resistivity of 5.7 × 10−6 Ω cm was obtained for approximately 97 nm Ag film on SiO2/Si substrate. The thickness was determined from the SEM cross section on the SiO2/Si substrate and also compared with XRF measurements. Polycrystalline cubic Ag reflections were identified from XRD for PALD Ag films deposited at 120 and 200 °C. Compared to W surface, where poor adhesion of the films was found, Co, Ni, TiN, Ti/TiN and SiO2 surfaces had better adhesion for silver films as revealed by SEM, TEM, and AFM images.