Effects of Kr sputtering on ultrathin PtHfSi film formation

• Published in: Japanese Journal of Applied Physics Vol. 53; no. 4S; pp. 4 - 1-04EB06-4
• Main Authors: Yoshimura, Yasuhiko, Ohmi, Shun-ichiro
• Format: Journal Article
• Language: English
• Published: The Japan Society of Applied Physics 01.04.2014
• Subjects: Crystallinity; Deposition; Formations; Hafnium; MOSFETs; Platinum; Sputtering; Three dimensional; X-ray diffraction
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.53.04EB06

For the MOSFET scaling, a three-dimensional (3D) MOSFET is required. Kr sputtering is considered to be suitable for metal deposition on a 3D structure in terms of step coverage compared with conventional Ar sputtering. In this study, we investigated the effects of sputtering gas on the silicidation of PtHfSi to obtain a high performance and ultrathin silicide. At first, we confirmed the crystallinity of the as-deposited films by X-ray diffraction (XRD). This result suggested that better crystallinity of the as-deposited films was obtained in the case of Kr sputtering. A Pt (12 nm)/Hf (8 nm)/n-Si(100) stacked layer was formed by Ar and Kr sputtering. Silicidation at 400 °C for 1 h in N2 ambient was carried out. The thicknesses of PtHfSi formed by Ar and Kr sputtering were 10 and 5.3 nm, respectively. The thinner film formation under the same silicidation condition was probably caused by the reduction of the diffusion coefficient during silicidation, which was caused by the improvement of Pt and Hf crystallinity.