Preliminary growth of metallic co films by thermal atomic layer deposition using RCpCo(CO)2 and alkylamine precursors

Abstract

ALD-metallic films are typically deposited with assistant of plasma due to lack of suitable reducing co-reactants. In this work, we propose to use RCpCo(CO)2, a cobalt precursor with cyclopentadienyl (Cp) ligand (R = H) or its trimethylsilylderivative (R = TMS), and tert-Butyl amine (tBuNH2) as co-reactant to grow metallic Co films by thermal atomic layer deposition (T-ALD). The influence of Co precursor type, substrate type and thermal treatment on the film growth, composition, and phase structure of the Co films was investigated. The results show that the ALD-Co processes exhibit similar temperature window from 275 °C to 325 °C, and the growth rate of Co films deposited from CpCo(CO)2 on Si substrate is about 0.045 nm/cycle, which is higher than that of using TMSCpCo(CO)2 (0.03 nm/cycle). Thermal annealing and Pt substrate can promote the crystallization and growth of Co crystals. The ALD-Co films grown by CpCo(CO)2 showed relatively low resistivity of 10.6 μΩ·cm and considerable conformality, indicating a significant application potential.