Mechanical properties of sputtered silicon oxynitride films by nanoindentation

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2008-08, Vol.489 (1), p.294-301
• Main Authors: Liu, Yan, Lin, I.-Kuan, Zhang, Xin
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Creep; Exact sciences and technology; Mechanical and acoustical properties; Nanoindentation; Physical properties of thin films, nonelectronic; Physics; Shear transformation zone; Silicon oxynitride; Sputtering; Stress exponent; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2008.01.063

Silicon oxynitride (SiON) has received a great deal of attention in micro-electro-mechanical system (MEMS) integration due to its composition-dependent tunability in optical, electronic and mechanical properties. In this work, silicon oxynitride films with different oxygen and nitrogen content were deposited by RF magnetron sputtering. Energy dispersive X-ray (EDX) spectroscopy and Fourier-transform infrared (FT-IR) spectroscopy were employed to characterize the SiON films with respect to stoichiometric composition and atomic bonding structure. Time-dependent plastic deformation (creep) of SiON films were investigated by depth-sensing nanoindentation at room temperature. Young's modulus and indentation-hardness were found correlated with the nitrogen/oxygen ratio in SiON films. Results from nanoindentation creep indicated that plastic flow was less homogenous with increasing nitrogen content in film composition. Correspondingly, a deformation mechanism based on atomic bonding structure and shear transformation zone (STZ) plasticity theory was proposed to interpret creep behaviors of sputtered SiON films.