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Improvement in ferroelectricity and breakdown voltage of over 20-nm-thick HfxZr1−xO2/ZrO2 bilayer by atomic layer deposition
- Source :
- Applied Physics Letters. 117:232902
- Publication Year :
- 2020
- Publisher :
- AIP Publishing, 2020.
-
Abstract
- The ferroelectricity of metal–ferroelectric–metal capacitors with a ferroelectric HfxZr1−xO2/ZrO2 (HZO/ZO) bilayer thicker than 20 nm formed by atomic layer deposition and postdeposition annealing at 600 °C was investigated. The HZO/ZO capacitors exhibited a higher remanent polarization (2Pr = Pr+ − Pr−) and breakdown voltage (Vbd) than capacitors with a HfxZr1−xO2 (HZO) single layer. In particular, a HZO (15 nm)/ZO(10 nm) (HZ15Z10) capacitor exhibited excellent Vbd and 2Pr values of 6.7 V and 14 μC/cm2, respectively, which are much higher than those (4.3 V and 10 μC/cm2, respectively) for a HZO (15 nm) (HZ15) capacitor. The HZ15Z10 capacitor also exhibited higher endurance, a smaller wake-up effect (∼5%), and superior fatigue properties up to 108 switching cycles, compared to a HZ15 capacitor, which exhibited a large wake-up effect (∼15%) and large 2Pr degradation at 108 cycles. The wake-up behavior is attributed to domain depinning mainly related to the redistribution of oxygen vacancies and transformation from the nonferroelectric phase to the ferroelectric orthorhombic (O) phase during field cycling. The HZO/ZO bilayer grew a larger grain size with the ZO nucleation layer, which is twice as large as that of the HZO single layer, and the former structure exhibited more stable bulk-like ferroelectricity. Although the ferroelectric O phase in HZO decreased with increasing HZO thickness, the HZO/ZO structure had a larger fraction of the O phase than the HZO structure. Considering the manufacturing process of ferroelectric devices, these thick HZO/ZO bilayers are promising ferroelectric materials.
- Subjects :
- 010302 applied physics
Materials science
Physics and Astronomy (miscellaneous)
Annealing (metallurgy)
Bilayer
Analytical chemistry
Nucleation
02 engineering and technology
021001 nanoscience & nanotechnology
01 natural sciences
Ferroelectricity
Atomic layer deposition
Phase (matter)
0103 physical sciences
Breakdown voltage
Orthorhombic crystal system
0210 nano-technology
Subjects
Details
- ISSN :
- 10773118 and 00036951
- Volume :
- 117
- Database :
- OpenAIRE
- Journal :
- Applied Physics Letters
- Accession number :
- edsair.doi...........d874863123df102c3350a82989b2bf3e
- Full Text :
- https://doi.org/10.1063/5.0029709