Reliability of ultra-thin titanium dioxide (TiO 2) films on strained-Si

• Published in: Thin solid films 2008-11, Vol.517 (1), p.27-30
• Main Authors: Bera, M.K., Mahata, C., Maiti, C.K.
• Format: Article
• Language: English
• Subjects: Charge carriers: generation, recombination, lifetime, trapping, mean free paths; Charge trapping; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Dielectric thin films; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electrical properties of specific thin films; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; High-k gate dielectric; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Oxide reliability; Physics; Strained-Si
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2008.08.008

Ultra-thin high-k titanium oxide (equivalent oxide thickness ~ 2.2 nm) films have been deposited on strained-Si/relaxed-Si 0.8Ge 0.2 heterolayers using titanium tetrakis iso-propoxides (TTIP) as an organometallic source at low temperature (< 200 °C) by plasma enhanced chemical vapor deposition (PECVD) technique in a microwave (700 W, 2.45 GHz) plasma cavity discharge system at a pressure of 66.67 Pa. The trapping/detrapping behavior of charge carriers in ultra-thin TiO 2 gate dielectric during constant current (CCS) and voltage stressing (CVS) has been investigated. Normalized trapping centroid and trapped charge density variation with injected fluences have been investigated and also empirically modeled. Oxide lifetime is predicted using empirical reliability model developed. Dielectric breakdown and reliability of the dielectric films have been studied using constant voltage stressing. A high time-dependent dielectric breakdown (TDDB, t bd > 1000 s) is observed under high constant voltage stress.