Surface roughness reducing effect of iodine sources (CH3I, C2H5I) on Ru and RuO2 composite films grown by MOCVD

Ru and RuO2 composite films were deposited on TiN/Ti/Si substrate by metal–organic chemical vapor deposition (MOCVD) for application as the bottom electrode of a high density DRAM capacitor. The effects of iodine sources (CH3I, C2H5I) on composite films deposited at 300 °C were investigated. Iodine sources enhanced nucleation dramatically at the initial deposition stage, and the surface roughness of the films was reduced considerably. The root-mean-square (r.m.s.) surface roughness of composite films that were grown up to 1000 Å with no addition, CH3I and C2H5I were 162, 48 and 38 Å, respectively. Moreover, iodine sources did not affect the orientation or deposition rate of films.