Low-Temperature Low-Resistivity PEALD TiN Using TDMAT under Hydrogen Reducing Ambient

Titanium nitride (TiN) films were deposited using plasma-enhanced atomic layer deposition (PEALD) from the organometallic precursor tetrakis-dimethyl-amino-titanium (TDMAT) with hydrogen (H 2 ) as a coreactant. Low-resistivity values lying from 210 to 275 μΩ cm were achieved for 10 nm thick films deposited at low temperature: 150°C. The effects of temperature, plasma time, and plasma power were investigated. It was demonstrated that the chemical reaction is complementary and self-limiting. A minimum energy is necessary to reach the low-resistivity plateau. Chemical and physical properties of the films are also reported and a surface reaction mechanism is proposed. It is suggested that after TDMAT chemisorption to the surface, amines are removed by hydrogen radicals, and at the same time, titanium carbide bonds (Ti-C) are formed. The low resistivity results from the presence of Ti 2 C or Ti 2 N phases in the PEALD TiN film. The industrial viability of this process was also evaluated on 300 mm wafers. Good performances were obtained on wafer-to-wafer uniformity and step coverage, while some improvements related to the within-wafer uniformity are required.