Ag films grown by remote plasma enhanced atomic layer deposition on different substrates (original) (raw)

2016, Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films

Silver (Ag) layers were deposited by remote plasma enhanced atomic layer deposition (PALD) using Ag(fod)(PEt 3) (fod ¼ 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 SiO 2 , 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 Â 10 À6 X cm was obtained for approximately 97 nm Ag film on SiO 2 /Si substrate. The thickness was determined from the SEM cross section on the SiO 2 /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 SiO 2 surfaces had better adhesion for silver films as revealed by SEM, TEM, and AFM images. V