Influence of graded doping on the long-term reliability of Nb-doped lead zirconate titanate films

Zhu, Wanlin; Akkopru-Akgun, Betul; Yang, Jihyun; Fragkiadakis, Charalampos; Wang, Ke; Ko, Song Won; Mardilovich, Peter; Trolier-McKinstry, Susan

doi:10.1016/j.actamat.2021.117251

Cited by 5 publications

(4 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If the electronic charge carrier compensation is spread out over a large volume (further from the electrode interface), for example by a graded doping concentration, the highly accelerated lifetime test (HALT) lifetime can be increased. 10,11) 2) For films exposed to high relative humidity values, failure can be induced by voltage-induced water splitting, with subsequent migration of oxygen and hydrogen through the electrodes and/or the film. 12) This failure mechanism can be eliminated with appropriate moisture protection of the MEMS structure.…”

Section: Introductionmentioning

confidence: 99%

“…Even higher lifetimes up to 94 h measured under the same conditions can be achieved when graded doping is employed, as mentioned above. 10,11) It should be noted that whereas self-heating is expected to be very modest under DC electric fields, unipolar AC field driving can induce self-heating that could accelerate failure. 16) However, there are many factors influencing the PZT film lifetime under DC voltage that are still incompletely understood.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reliability of piezoelectric films for MEMS

Trolier-McKinstry,

Zhu,

Akkopru-Akgun

et al. 2023

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

Thin films based on PbZr1-xTixO3 and K1-xNaxNbO3 are increasingly being commercialized in piezoelectric microelectromechanical systems (MEMS) due to the comparatively low drive voltages required relative to bulk actuators, as well as the facile approach to making sensor or actuator arrays. As these materials are incorporated into devices, it is critically important that they operate reliably over the lifetime of the system. This paper discusses some of the factors controlling the electrical and electromechanical reliability of PZT-based piezoMEMS films. In particular, it will be shown the gradients in the Zr/Ti ratio through the depth of the films are useful in increasing the lifetime of the films under DC electrical stresses.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reliability of piezoelectric films for MEMS

Trolier-McKinstry,

Zhu,

Akkopru-Akgun

et al. 2023

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The optimization process was carried out under varying deposition pressures, laser frequencies, and substrate temperatures for growth on Pt/Ti/SiO 2 /Si substrates (KOTech LLC) with a 60 nm Nb-doped PZT seed layer. [48,49] Mn PHEO films were synthesized with 175 mTorr, 90%O 3 /10%O 2 deposition ambient, at a 630 °C substrate temperature and 10 Hz laser frequency. Identical processing conditions were used for Al PHEO films.…”

Section: Methodsmentioning

confidence: 99%

Electrocaloric Effect of Perovskite High Entropy Oxide Films

Son

Zhu

Trolier‐McKinstry

2022

Adv Elect Materials

Self Cite

View full text Add to dashboard Cite

Such small-scale cooling is also of interest for on-chip cooling of semiconductor circuits. [6] In 2020, data centers in the United State used an estimated 75 billion kWh, more than 2% of the nation's total energy consumption. Approximately half of this energy was spent on cooling these centers. [7] Advanced cooling technology that directly cools integrated circuits (ICs) (rather than the entire data center) offers an alternative. Furthermore, IC miniaturization has increased the power density of a packaged chip to 10 6 W cm −2 in 2018; power densities continue to rise, and often induce highly nonuniform heat generation. [8] It has been reported that more than 50% of IC failures are related to thermal control; this rate is expected to increase with further miniaturization. [9] Therefore, new approaches for local cooling of IC are needed. [10] Solid-state cooling, a potential solution, is highly compact, efficient, and environmentally friendly. Research involving thermoelectric, electrocaloric, and magnetocaloric effects is promising. [11][12][13] In 2006, large electrocaloric effects were observed in PZT thin films. [14] Unlike magnetocaloric and barocaloric materials, the electrocaloric effect does not require bulky external magnets or pressure apparatus. Electrocalorics enable relatively good energy efficiency that can be further improved via charge recovery. [15,16] Achieving large temperature changes in the electrocaloric material necessitates inducing large field-induced entropy changes. For this purpose, relaxor ferroelectrics are of special interest due to the disordered polarization and polar nanoregions. [17] A potential additional contribution to the entropy change in a ferroelectric-based material is to use high compositional complexity, e.g. through entropy engineering to further disorder the polarization on a local scale. In 2004, entropy stabilization of metallic alloys was introduced. [18,19] In 2015, the concept was broadened to include entropy stabilized oxides. [20] Various entropy stabilized oxides (ESO) have shown high dielectric constants, superior ionic conductivity, and extremely high-temperature stability; that is, entropy stabilization provides an additional approach to property tunability with respect to enthalpy-based compositional design. [21][22][23] In cases where reversible phase transformations have not yet been demonstrated, potential ESO may be called high entropy oxides (HEO). [24] Triggered by the novel concept, several attempts to investigate the electrocaloric effect (ECE) based on HEO have been made. A-site disordered HEO ceramics show good This paper describes two perovskite high entropy oxide (PHEO) compositions: Pb(Hf 0.2 Zr 0.2 Ti 0.2 Nb 0.2 Mn 0.2 )O 3 (Mn PHEO) and Pb(Hf 0.2 Zr 0.2 Ti 0.2 Nb 0.2 Al 0.2 )O 3 (Al PHEO). Powders are prepared by conventional solid state sintering by first pre-reacting the B-site oxides, then adding PbO. Phase pure Mn PHEO powder is obtained following calcination of the mixed powders at 750 °C for 240 min; however, secondary phases persist...

show abstract

“…PZT thin films have a relatively low activation-energy for 𝑉𝑉 𝑂𝑂 * * migration (𝐸𝐸 𝐴𝐴 ~0.6 𝑒𝑒𝑉𝑉) 38,39 . Also, undoped PZT is inherently acceptor-dominated and has a 𝑉𝑉 𝑂𝑂 * * -concentration considerably higher than donor-doped PZT, and no multivalent acceptor-dopants, such as Mn to compensate for cathodic charge-injection 40 39 . In the absence of visible cracks and ETB (hard breakdown events), it is plausible that devices can be partially rejuvenated from soft breakdown events by reversing the electric field at elevated temperatures and drive 𝑉𝑉 𝑂𝑂 * * from the cathode interface back into the bulk of the film.…”

mentioning

confidence: 99%

Reliable Pb(Zr,Ti)O3-based thin film piezoelectric micromirrors for space-applications

Dahl-Hansen

Gjessing

Mardilovich

et al. 2022

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

Although Pb(Zr,Ti)O3 (PZT) piezoelectric thin films are finding widespread applications on Earth, it is yet unclear if they are suitable for space-related applications. In space, their long-term reliability is a significant concern due to the difficulties of repairing and replacing malfunctioning devices. In this work, PZT thin film micromirrors for compact interferometric 3D imaging systems have been exposed to operating conditions encountered on a space mission and tested according to criteria set by the European Space Agency. Thermal cycling in vacuum, sinusoidal and random mechanical vibrations, and [Formula: see text]-radiation with and without bias did not degrade key functional device properties of the micromirror such as angular deflection, resonance frequency, polarization, and permittivity. Apart from [Formula: see text]-radiation, stressing the devices enhanced their large-signal angular deflection and improved their electrical lifetime compared to pristine devices. Their dielectric and ferroelectric characteristics remained comparable to that of a lab-scale environment. Simultaneously applying a 10 V field-down bias while [Formula: see text]-radiating the micromirrors changed the capacitance-field and polarization-field characteristics and enhanced the electrical imprint. After stress-testing, the median time-to-failure in moderate acceleration conditions of 150 kV/cm and 175 °C ranged from 1.95 to 2.64 h, close to 2.11 h as measured for a reference group. All actuator membranes had shorter electrical lifetimes, smaller voltage acceleration factors, and smaller activation energies, ranging from 2.56 to 2.88 V−1 and 1.03 to 1.09 eV, than simple bonding pads. This work is a device-level report covering a full set of space-relevant tests demonstrating that PZT-based thin film piezomicroelectromechanical systems technology is space-ready.

show abstract

Influence of graded doping on the long-term reliability of Nb-doped lead zirconate titanate films

Cited by 5 publications

References 47 publications

Reliability of piezoelectric films for MEMS

Reliability of piezoelectric films for MEMS

Electrocaloric Effect of Perovskite High Entropy Oxide Films

Reliable Pb(Zr,Ti)O3-based thin film piezoelectric micromirrors for space-applications

Contact Info

Product

Resources

About