Interface and plasma damage analysis of PEALD TaCN deposited on HfO2 for advanced CMOS studied by angle resolved XPS and C-V

• Published in: Applied surface science Vol. 303; pp. 388 - 392
• Main Authors: PIALLAT, Fabien, BEUGIN, Virginie, GASSILLOUD, Remy, DUSSAULT, Laurent, PELISSIER, Bernard, LEROUX, Charles, CAUBET, Pierre, VALLEE, Christophe
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 01-06-2014
• Subjects: Chemical bonds; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Electric power generation; Electrodes; Exact sciences and technology; Hafnium; Hafnium oxide; Physics; Reduction; X-ray photoelectron spectroscopy; Inorganic compounds; Angular resolution; Transition element compounds; Hafnium oxide; Tantalum; High-k dielectric; Transition elements; Hafnium; XPS; Damage; Interface; Metal gate; X-ray photoelectron spectra
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2014.03.011

Plasma enhanced atomic layer deposition (PEALD) TaCN deposited on HfO2 was studied by X-ray photoelectron spectroscopy (XPS) to understand the reactions taking place at the interface and connect them with C-V electrical characteristics of MOS devices. Moreover, angular resolved XPS (AR-XPS) was used for composition depth profiling of TaCN/HfO2/SiO2/Si stacks. Clear oxidation of the metal electrode through Ta--O bonding formation and migration of N in the dielectric with Hf--N are shown. These modifications of chemical bonding give an insight on the electrical results. Low equivalent oxide thicknesses (EOT), as low as 0.89nm and current leakage improvement by more than 5 decades, are observed for deposition with low plasma power and can be related to HfN content in HfO2 layer. The increase of plasma power used for TaCN deposition results in densification of the layer and promotes the creation of TaC in TaCN material. However H2 plasma has an impact on HfO2 with a reduction and scattering of the measured current leak gain. TaCN/HfO2 interface is also impacted with further creation of TaOx, leading to an increase of EOT when plasma power is increased. Based on these findings, reaction mechanisms with the corresponding Gibbs free energy are proposed.