Germanium aluminum nitride thin films for piezo-MEMS devices

Mizuno, Takaaki; Umeda, Kentaro; Aida, Yasuhiro; Honda, A.; Akiyama, Morito; Nagase, Takako; Kobayashi, Masato

doi:10.1109/transducers.2017.7994440

Cited by 7 publications

(6 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are some studies of dopants that reverse the polarity of AlN films. [52][53][54] These studies have pointed out that Al vacancy (V Al ) in AlN is an important parameter for polarity inversion. Doping Li and Nb may introduce V Al into AlN because their ion valences are different from Al's.…”

Section: Discussionmentioning

confidence: 99%

Piezoelectric properties of LiM-doped (M = V, Nb, Ta, or Zr) AlN thin films

Terada

Kimura

Sasaki

et al. 2021

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

Characterization of LiM-doped (M = V, Nb, Ta, or Zr) piezoelectric aluminum nitride ((Li y M 1−y ) x Al 1−x N) was performed by first-principles calculations and experimental approaches. The calculation results show that for all (Li y M 1−y ) x Al 1−x N, piezoelectric coefficient d 33,f is increased by increasing the LiM doping concentration x up to 0.25. In comparison to the calculation results, the experimental results reveal that only (Li y Nb 1−y ) x Al 1−x N has increased piezoelectric coefficient d 33 . The absolute value of d 33 was 9.54 pC N −1 at x = 0.15 ((Li 0.45 Nb 0.55 ) 0.15 Al 0.85 N) due to elastic softening of the elastic modulus E. In addition, the research investigates how LiM doping inverts the polarity depending on x. Insulating performance was also evaluated, revealing that LiM doping induces resistivity degradation down to 10 7 and 10 9 Ω•cm for M = V and Nb, respectively. Results for d 33 indicate that (Li y M 1−y ) x Al 1−x N systems represented by M = Nb have potential as piezoelectric materials for MEMS applications.

show abstract

Section: Discussionmentioning

confidence: 99%

Piezoelectric properties of LiM-doped (M = V, Nb, Ta, or Zr) AlN thin films

Terada

Kimura

Sasaki

et al. 2021

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…There are many reports regarding polarity change in wurtzite by composition or fi lm preparation conditions [20][21][22][23][24]. It is reported that the polarity of AlN films reversed by doping Ge [23] or Si [24].…”

Section: Polarity Inversionmentioning

confidence: 99%

Influence of the Li and M (M = V, Nb, Ta, or Zr) Composition Ratio on the Piezoelectric Properties of LiM-doped AlN Films

Terada

Kimura

Inoue

2022

Int.J.Soc.Mater.Eng.Resour.

View full text Add to dashboard Cite

This paper describes the piezoelectric properties of LiM-doped (M = V, Nb, Ta, or Zr) aluminum nitride ((Li y M 1-y ) x Al 1-x N) films with respect to the composition ratio of Li and M. Films of (Li y M 1-y ) x Al 1-x N were prepared by a radio frequency magnetron sputtering method and characterized by crystal structure, as well as electrical properties such as the piezoelectric coeffi cient d 33 and resistivity ρ. The fi lms for M = Nb with x = 0.13-0.20 and y = 0.41-0.49 showed |d 33 | = 8.26-9.54 pC/N, which were 21-38% larger than non-doped AlN. On the other hand, the fi lms for M = V, Ta, and Zr exhibited a decrease in piezoelectricity. The piezoelectric properties in (Li y M 1-y ) x Al 1-x N fi lms against M can be mainly explained by the combination of the following factors: crystallinity, lattice parameter ratio c/a, ρ, orientation degree, and polarity inversion. This study revealed that the composition ratio of Li and M gives (Li y M 1-y ) x Al 1-x N fi lms diff erent behaviors on physical properties and the films for M = Nb with similar stoichiometric compositions (y -0.5) are promising candidates as piezoelectric materials for micro-electro-mechanical systems.

show abstract

“…26,27) However, a PI AlN film with more than three-layers cannot be obtained by these polarity control methods. Recently, the polarity of the AlN film has been shown to be easily controlled by Si 28) or Ge 29,30) doping. We have demonstrated that the two-to eightlayered PI films can be obtained by alternately growing Alpolar AlN films and N-polar SiAlN films.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of c-axis oriented GeAlN films and applications to higher-order mode BAW resonators

Suzuki

Sekimoto

Kakio

2023

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

AlN film bulk acoustic wave (BAW) resonators and filters that operate at frequencies above 5 GHz are required for 5G and beyond 5G communication applications. However, the power-handling capability, Q factor, and electromechanical coupling in high-frequency AlN film BAW resonators will be degraded as a result of the significantly reduced thickness and volume of the devices. Higher-order mode BAW resonators with polarity inverted (PI) multilayered films can operate at high frequencies while maintaining the thickness and volume of the devices. In this study, we fabricated an eight-layered PI GeAlN/AlN film BAW resonator by alternately growing Al-polar AlN layers and N-polar GeAlN layers. The PI GeAlN/AlN film BAW resonator resonated in the 8th-order mode. The film thickness of the PI GeAlN/AlN film BAW resonator was approximately thirteen times larger than that of a single-layer AlN film BAW resonator operating in the same frequency range.

show abstract

Germanium aluminum nitride thin films for piezo-MEMS devices

Cited by 7 publications

References 11 publications

Piezoelectric properties of LiM-doped (M = V, Nb, Ta, or Zr) AlN thin films

Piezoelectric properties of LiM-doped (M = V, Nb, Ta, or Zr) AlN thin films

Influence of the Li and M (M = V, Nb, Ta, or Zr) Composition Ratio on the Piezoelectric Properties of LiM-doped AlN Films

Characteristics of c-axis oriented GeAlN films and applications to higher-order mode BAW resonators

Contact Info

Product

Resources

About