Characterization of Ferroelectric Characteristics for Hafnium Zirconium Oxide Capacitors with Refractory Electrodes

Abstract

We investigated the ferroelectric properties of Hf0.5Zr0.5O2 (HZO) metal-ferroelectric-metal (MFM) capacitors on various refractory electrodes, including TiN, TaN, W, and Mo. By comparing different electrodes and annealing temperature, we found that the MFM capacitors with TiN and W electrodes showed higher remanent polarization (2Pr) and lower leakage current for post-metal annealing (PMA) temperatures ranging from 400°C to 600°C. Moreover, the MFM capacitor with W electrode showed better saturated polarization-voltage (P-V) curve and less “wake up effect” during the polarization switching cycles, while the MFM capacitor with TiN electrode showed the lowest leakage current. The correlation of crystallization quality studied by X-ray diffraction and the ferroelectric characteristics for each type of MFM capacitors were also presented and compared in this study.

Understanding the Effect of Top Electrode on Ferroelectricity in Atomic Layer Deposited Hf0.5Zr0.5O2 Thin Films

“…This is much higher than the samples of W top electrodes reported in other literature. ,, Since Mo has larger CTE than W. Such abnormal trends should not come from the strain change alone. Although the W top electrode with small thermal expansion coefficient was used, the 2Pr just reach 28 μC/cm 2 , lower than that with other top electrodes (such as TiN or Mo) at similar process conditions in other works. , In addition to the metal electrodes, the similar abnormal trend was also found in the oxide electrode. The CTE of ruthenium oxide (RuO 2 ) is 6.4 × 10 –6 K, which is lower than that of TiN (9.1 × 10 –6 K).…”

“…Figure 3d compares the remanent polarization (2Pr) of the MFM ferroelectric capacitor with these three kinds of electrodes in the previous works, and the details can be seen in Table S2. 14,20,22,24,27,28 The devices with W capping electrodes do not always exhibit maximum ferroelectricity. Our experimental results and the evidence in the literature strongly suggest that there are still other factors besides the strain caused by the top electrode that plays an important role in the induction of HZO film ferroelectricity.…”

Hafnia-Based High-Disturbance-Immune and Selector-Free Cross-Point FeRAM

“…Further HRTEM image with 10-and 100-nm BE devices suggests that the thickness of BE has great impact on layer roughness [19]. For TE thickness, TE stress applied on FE layer plays an important on device performance as many works have reported [23], [24], [25]. Devices in our work with TE thickness of 50 and 100 nm are characterized with results shown in Fig.…”

Improved ferroelectric and endurance properties of Hf0.5Zr0.5O2 thin films by a replacement indium-tin-oxide top electrode process

“…Besides, the oxygen scavenges effect from the TiN/FE-HfO 2 interface could induce oxygen vacancies [9], which lowers the free energy of the o-phase and alleviates the phase transition from the o-phase to the monoclinic phase during the cooling process. Therefore, only a few electrodes including TiN, TaN, W, RuO 2 , Ru, Mo, and Ir are found to achieve excellent ferroelectricity in HfO 2 fabricated by the atomic-layer-deposition (ALD) method [3,[10][11][12][13][14].…”