Ferroelectric Zr0.5Hf0.5O2 thin films for nonvolatile memory applications
Abstract
We report the observation of ferroelectricity in capacitors based on hafnium-zirconium-oxide. Hf0.5Zr0.5O2 thin films of 7.5 to 9.5 nm thickness were found to exhibit ferroelectric polarization-voltage hysteresis loops when integrated into TiN-based metal-insulator-metal capacitors. A remnant polarization of 16 μC/cm2 and a high coercive field of 1 MV/cm were observed. Further proof for the ferroelectric nature was collected by quasi-static polarization-voltage hysteresis, small signal capacitance-voltage, and piezoelectric measurements. Data retention characteristics were evaluated by a Positive Up Negative Down pulse technique. No significant decay of the initial polarization state was observed within a measurement range of up to two days.
- Publication:
-
Applied Physics Letters
- Pub Date:
- September 2011
- DOI:
- Bibcode:
- 2011ApPhL..99k2901M
- Keywords:
-
- dielectric hysteresis;
- dielectric polarisation;
- electric variables measurement;
- ferroelectric capacitors;
- ferroelectric coercive field;
- ferroelectric thin films;
- hafnium compounds;
- MIM devices;
- piezoelectricity;
- thin film capacitors;
- titanium compounds;
- zirconium compounds;
- 84.32.Tt;
- 84.37.+q;
- 85.50.Gk;
- Capacitors;
- Measurements in electric variables;
- Non-volatile ferroelectric memories