Details

Autor(en) / Beteiligte

• Weeks, Stephen L
• Pal, Ashish
• Narasimhan, Vijay K
• Littau, Karl A
• Chiang, Tony

Titel

Engineering of Ferroelectric HfO 2 -ZrO 2 Nanolaminates

Ist Teil von

• ACS applied materials & interfaces, 2017-04, Vol.9 (15), p.13440-13447

Ort / Verlag

United States

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• In this work, the ferroelectric properties of nanolaminates made of HfO and ZrO were studied as a function of the deposition temperature and the individual HfO /ZrO layer thickness before and after electrical field cycling. The ferroelectric response was found to depend on the structure of the nanolaminates before any postdeposition annealing treatment. After annealing with a TiN cap, an "antiferroelectric-like" response was obtained from nanolaminates deposited in an amorphous state at a lower temperature, whereas a ferroelectric response was obtained from nanolaminates deposited at a higher temperature, where crystallites were detected in thick films before annealing. As the individual layer thicknesses were decreased, an increased lattice distortion and a concurrent increase in remanent polarization were observed from the nanolaminates deposited at high temperatures. After field cycling, nanolaminates deposited at lower temperatures exhibited an antiferroelectric-like to ferroelectric transition, whereas those deposited at higher temperatures exhibited a larger remanent polarization. Finally, we demonstrate that by leveraging the proper choice of process conditions and layer thickness, remanent polarizations exceeding those of the HfZrO solid solution can be obtained.