Low-toxicity chemical solution deposition of ferroelectric Ca:HfO₂

Abstract

So far, a few chemical solution routes for the fabrication of ferroelectric HfO2 films have been reported. Most of them employ precursors, solvents or additives that are considered difficult to...

Optical, conductive, and ferroelectric properties of the first layer of dip-coated BiFeO3 films from methoxyethanol and acetic acid-based chemical dissolvents

“…It is observed that increasing U 0 from 2 cm min −1 to 5 cm min −1 does not cause significant variations in the piezoelectric response, only slightly reducing the scatter of the data as seen from the error bars. However, an increase of U 0 to 10 cm min −1 does result in an increase of the piezoelectric coefficient of d From d eff results, we rule out the effect of depolarization fields, as these are most noticeable in ferroelectric films with thicknesses below 10 nm where a stable paraelectric phase coexists with a metastable ferroelectric one, resulting in pinched hysteresis (resembling a double loop), as reported in [34,35]. There, the injection and trapping of charges into pre-existing interfacial defects during field cycling (wake-up) screens the depolarization field, stabilizing the ferroelectricity [34,35].…”

“…However, an increase of U 0 to 10 cm min −1 does result in an increase of the piezoelectric coefficient of d From d eff results, we rule out the effect of depolarization fields, as these are most noticeable in ferroelectric films with thicknesses below 10 nm where a stable paraelectric phase coexists with a metastable ferroelectric one, resulting in pinched hysteresis (resembling a double loop), as reported in [34,35]. There, the injection and trapping of charges into pre-existing interfacial defects during field cycling (wake-up) screens the depolarization field, stabilizing the ferroelectricity [34,35]. However, an attenuation of the PR and piezoelectric coefficient d eff in BiFeO 3 films has been reported as the thickness decreases from 150 nm to <10 nm [36].…”

Recent progress on defect-engineering in ferroelectric HfO2: The next step forward via multiscale structural optimization

“…Ferroelectric HfO 2 films with high P r values have been fabricated by pulsed laser deposition (PLD), 31 ALD, 109 sputtering deposition, 110,111 and chemical solution deposition (CSD). 85,112…”

“…Ferroelectric HfO 2 films with high P r values have been fabricated by pulsed laser deposition (PLD), 31 ALD, 109 sputtering deposition, 110,111 and chemical solution deposition (CSD). 85,112 Each of these methods have their advantages and disadvantages, and the most intensively used deposition method is ALD due to its ultra-thin growth, low-temperature deposition, and semiconductor process compatibility, etc. 113 ALD can generally control the Zr x Hf 1Àx O 2 by controlling the number of Zr layers in the HfO 2 -based system.…”

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

“…22 Yet, in the present case, the films are synthesized by employing a flexible CSD route using stable and less toxic precursors. 18 We propose that our facile chemical approach, along with the use of some other promising dopants such as La and Y, could improve remnant polarization values by controlling crystal orientations in HfO 2 -based films and produce thick ferroelectric films that are fully competitive with those deposited by other techniques. 23…”