Addition of yttrium into HfO2 films: Microstructure and electrical properties

作者：Dubourdieu C^*; Rauwel E; Roussel H; Ducroquet F; Hollaender B; Rossell M; Van Tendeloo G; Lhostis S; Rushworth S

来源：Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films , 2009, 27(3): 503-514.

DOI：10.1116/1.3106627

• annealing
• attenuated total reflection
• crystal structure
• electron diffraction
• hafnium compounds
• infrared spectra
• lattice constants
• MOCVD
• permittivity
• thin films
• X-ray diffraction
• X-ray photoelectron spectra
• yttrium

The cubic phase of HfO2 was stabilized by addition of yttrium in thin films grown on Si/SiO2 by metal-organic chemical vapor deposition. The cubic phase was obtained for contents of 6.5 at. % Y or higher at a temperature as low as 470 degrees C. The complete compositional range (from 1.5 to 99.5 at. % Y) was investigated. The crystalline structure of HfO2 was determined from x-ray diffraction, electron diffraction, and attenuated total-reflection infrared spectroscopy. For cubic films, the continuous increase in the lattice parameter indicates the formation of a solid-solution HfO2-Y2O3. As shown by x-ray photoelectron spectroscopy, yttrium silicate is formed at the interface with silicon; the interfacial layer thickness increases with increasing yttrium content and increasing film thickness. The dependence of the intrinsic relative permittivity epsilon(r) as a function of Y content was determined. It exhibits a maximum of similar to 30 for similar to 8.8 at. % Y. The cubic phase is stable upon postdeposition high-temperature annealing at 900 degrees C under NH3.

• 出版日期2009-5