(001)-Oriented Sr:HfO₂ Ferroelectric Films Deposited by a Flexible Chemical Solution Method

Remnant polarization values of ferroelectric HfO2-based films depend on proper control of the polar orthorhombic phase crystallization and the orientation of the polar domains. Most of the best quality films reported so far are (111)-oriented. While the largest polarization is expected in (001)-oriented films, with the polar axis out of the plane, such orientation is far less common. This paper demonstrates that highly (001)/(010)-oriented heterostructures of Sr:HfO2 on Pt(111)-buffered Si can be attained in layered films deposited by a recently reported chemical solution deposition route. The oriented films display the short c-axis out of plane, giving place to a longer a lattice in plane. By tailoring the duration of rapid thermal processing, such oriented films produce highly ferroelectric, leakage-free capacitors. After wake-up cycling, a remnant polarization of 17 μC/cm2, which is the highest reported for this dopant and technique, was achieved. Even though optimization is still needed to improve the electrical cyclability, our facile approach produces high-k, highly oriented Sr:HfO2 films, through chemical deposition and annealing, and shows that the crystal orientations and phase purity of HfO2-based films can be further optimized by cost-effective chemical methods.</p

Lead-free KNN-based thin films obtained by pulsed laser deposition

In this work, 0.96(K0.48Na0.52)0.95Li0.05Nb0.94Sb0.06O3−0.04Ba0.94Ca0.06ZrO3 (KNLNS-BCZ) and 0. 9S(K0.48Na0.52)0.95Li0.05Nb0.95Sb0.05O3−0.02Ba0.5(Bi0.5Na0.5)0.5ZrO3 (KNLNS-BBNZ) ferroelectric thin films were obtained by pulsed laser deposition. The structural, and morphological characteristics were studied to determine the best deposition parameters and analyse the piezoelectric properties. The studied deposition parameters were temperature, laser fluence, oxygen partial pressure and frequency. These parameters impact important characteristics of the thin films like grain morphology, thickness, and roughness. KNLNS-BCZ thin films with pure perovskite structure, homogeneous grain growth, and thickness ≥100 nm were fabricated at 700∘C,2J/cm2,300 mTorr, and frequencies of 5 Hz and 10 Hz. These films presented good ferroelectric behaviour and piezoelectric coefficient d 33eff of 83.80 pm/V and 25.80 pm/V, respectively

Lead-free KNN-based thin films obtained by pulsed laser deposition

In this work, 0.96(K0.48Na0.52)0.95Li0.05Nb0.94Sb0.06O3−0.04Ba0.94Ca0.06ZrO3 (KNLNS-BCZ) and 0. 9S(K0.48Na0.52)0.95Li0.05Nb0.95Sb0.05O3−0.02Ba0.5(Bi0.5Na0.5)0.5ZrO3 (KNLNS-BBNZ) ferroelectric thin films were obtained by pulsed laser deposition. The structural, and morphological characteristics were studied to determine the best deposition parameters and analyse the piezoelectric properties. The studied deposition parameters were temperature, laser fluence, oxygen partial pressure and frequency. These parameters impact important characteristics of the thin films like grain morphology, thickness, and roughness. KNLNS-BCZ thin films with pure perovskite structure, homogeneous grain growth, and thickness ≥100 nm were fabricated at 700∘C,2J/cm2,300 mTorr, and frequencies of 5 Hz and 10 Hz. These films presented good ferroelectric behaviour and piezoelectric coefficient d 33eff of 83.80 pm/V and 25.80 pm/V, respectively