Abstract

Ru films were successfully prepared by plasma-enhanced atomic layer deposition (PEALD) using Ru(EtCp)_2 and NH_3 plasma. To optimize Ru PEALD process, the effect of growth temperature, NH_3 plasma power and NH_3 plasma time on the growth rate and preferred orientation of the deposited film was systemically investigated. At a growth temperature of 270circC and NH_3 plasma power of 100W, the saturated growth rate of 0.038 nm/cycle was obtained on the flat SiO_2/Si substrate when the Ru(EtCp)_2 and NH_3 plasma time was 7 and 10 sec, respectively. When the growth temperature was decreased, however, an increased NH_3 plasma time was required to obtain a saturated growth rate of 0.038 nm/cycle. Also, NH_3 plasma power higher than 40 W was required to obtain a saturated growth rate of 0.038 nm/cycle even at a growth temperature of 270°C. However, (002) preferred orientation of Ru film was only observed at higher plasma power than 100W. Moreover, the saturation condition obtained on the flat SiO_2/Si substrate resulted in poor step coverage of Ru on the trench pattern with an aspect ratio of 8:1, and longer NH_3 plasma time improved the step coverage.

• Keywords: Ru films;Plasma-enhanced atomic layer deposition;NH_3 plasma;