| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Controlled Synthesis, Processing, and Applications of Structural and Functional Nanomaterials
|
| Presentation Title |
Low Temperature Synthesis of Metastable Tetragonal Yttria Doped Hafnia T-(Y-HfO2) Nanoparticles Through Mechanochemical Processing and Annealing |
| Author(s) |
Zanlin Qiu, Cheng-han Li, Joerg R Jinschek, Pelagia-Irene (Perena) Gouma |
| On-Site Speaker (Planned) |
Zanlin Qiu |
| Abstract Scope |
Tetragonal hafnia (T-HfO2) has shown great potential in MOSFET applications, because of its high dielectric constant and wide bandgap. However, a temperature of 1500-1800 ℃ and a critical particle size of 4-10 nm is required to stabilize metastable T-HfO2, preventing a stable T-phase at room temperature. Here, a viable route for stabilizing thermodynamically unfavored phases in the HfO2 system is described. Specifically, yttrium(Y)-doped T-HfO2 nanoparticles have been stabilized with a size of ~58nm using mechanochemical processing followed by subsequent annealing. Structural characterization using XRD, Raman spectroscopy and HRTEM imaging revealed the transformation pathway as M-HfO2 →amorphous phase + T-HfO2 seeds → T-HfO2. (Note: the first process occurs during milling and the second process occur during annealing) The stabilization of T-HfO2 is attributed to the grinding effect in the milling process, decreasing the grain size and simultaneously increasing the surface energy into the range stabilizing the tetragonal phase |