[Paper] Atomic Layer Deposition of Co using N2/H2 plasma as a Reactant




Atomic Layer Deposition of Co using N2/H2 plasma as a Reactant, Jaehong Yoon, Han-Bo-Ram Lee, Doyoung Kim, Taehoon Cheon, Soo-Hyun Kim, and Hyungjun Kim, Journal of The Electrochemical Society, 2011


http://dx.doi.org/10.1149/2.077111jes


Abstract


Cobalt thin films were deposited by plasma-enhanced atomic layer deposition (PE-ALD) using CoCp2 as a precursor and N2/H2 plasma as a reactant.We systematically investigated the changes in Co film properties depending on N2/H2 gas flow ratio to study the role of N during PE-ALD Co.With increasing N2 flow ratio, the resistivity decreased reaching minimum value at fN2/H2 = 0.25 ~ 0.33, which corresponds to the atomic ratio in NH3 molecule, and then increased. With only N2 or H2 plasma, films with very high sheet resistance over 1 M/sq were deposited. The chemical compositions of Co films were analyzed by x-ray photoelectron spectroscopy (XPS) and thickness and conformality were determined by x-ray reflectometry (XRR) and field emission scanning electron microscopy (FE-SEM), respectively. Then, the silicidation of PE-ALD Co films producing epitaxial CoSi2 were investigated by x-ray diffraction (XRD) and high-resolution cross-sectional transmission electron microscopy (HR-XTEM).