High-Overtone Thin Film Ferroelectric AlScN-on-Silicon Composite Resonators

Park, Mingyo; Wang, Jialin; Ansari, Azadeh

doi:10.1109/led.2021.3070274

Cited by 29 publications

(9 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The piezoelectric/ferroelectric alloy Sc x Al 1−x N is currently of great interest for making high piezoelectric coupling strength, and potentially switchable resonators [5], [10], [11], [12], [13]. The Sc 0.33 Al 0.67 N/AlN/NbN heterostructure (150 nm/50 nm/50 nm respectively) used here is grown on a 350 µm thick CMP-polished Si-face 4H-SiC substrate using RF-plasma-assisted molecular beam epitaxy.…”

Section: Growth Design and Fabrication A Heterostructure Growth And F...mentioning

confidence: 99%

“…The high frequency and power handling requirements for applications such as millimeter wave radar and 5G FR2 require novel strategies. Composite or overtone resonators, including high overtone mode bulk acoustic resonators (HBARs) are a promising solution [2], [3], [4], [5], [6]. HBARs are thin film metal/piezoelectric/metal transducers on a thicker substrate (Fig.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

X–Ka Band Epitaxial ScAlN/AlN/NbN/SiC High-Overtone Bulk Acoustic Resonators

Gokhale

Hardy

Katzer

et al. 2023

IEEE Electron Device Lett.

View full text Add to dashboard Cite

This letter presents the first demonstration of epitaxial scandium aluminum nitride (ScAlN) based high-overtone bulk acoustic resonators (epi-HBARs) with over 1600 acoustic cavity resonance modes spanning the X -Ka bands (8 GHz -40 GHz). We present data up to the 2150 th overtone (39.99 GHz). This is an unprecedented result even for HBARs, which often exhibit hundreds of overtones. The measurements demonstrate the successful combination of multiple innovations, namely: a) the growth of ultra-thin, high quality Sc 0.33 Al 0.67 N (high Sc fraction), b) on an epitaxial heterostructure with lattice-and acoustic impedance-matched layers, and c) the selective etching of ScAlN on NbN. Key metrics for the ScAlN epi-HBARs include Q > 7000, f×Q > 10 14 Hz, and k 2 eff ×Q BVD > 0.22 at cryogenic temperatures for frequencies as high as 40 GHz (>500, >6 × 10 12 Hz, >0.1 at room temperature). Temperature trends motivate future investigation of unquantified high frequency acoustic loss mechanisms. Such robust RF MEMS epi-HBARs with piezoelectric drive and readout are promising candidates for compact microwave/millimeter wave signal processing elements.

show abstract

Section: Growth Design and Fabrication A Heterostructure Growth And F...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

X–Ka Band Epitaxial ScAlN/AlN/NbN/SiC High-Overtone Bulk Acoustic Resonators

Gokhale

Hardy

Katzer

et al. 2023

IEEE Electron Device Lett.

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4][5] Due to the brilliant piezoelectric coefficients superior to AlN (d 33 = 5 pC N -1 ), AlScN (d 33 = 25 pC N -1 ) has attracted extensive attentions in micro-electromechanical system (MEMS) applications related with bulk acoustic waves (BAWs) and surface acoustic waves (SAWs), [6][7][8][9] such as acoustic sensors, energy harvesters and radiofrequency (RF) filters. [10][11][12][13][14][15] AlScN is an ideal candidate to implement AO coupling interactions on SOI platform.…”

Section: Introductionmentioning

confidence: 99%

Acousto‐Optic Modulation in Silicon Waveguides Based on Piezoelectric Aluminum Scandium Nitride Film

Huang

Shi

et al. 2022

Advanced Optical Materials

View full text Add to dashboard Cite

In recent years, piezoelectric materials, such as AlN, lithium niobate (LN) and GaAs, are frequently applied to acoustooptic (AO) coupling interactions with great potentials. [16][17][18][19][20][21][22][23][24] With a travelling SAW actuated by the interdigital transducer (IDT), the optical waves in waveguides are scattered by the travelling refractive index gratings and frequencyshifted through Doppler effect. [25] The AO coupling in piezoelectric materials offers a promising way to implement on-chip AO modulation, microwave photonic filtering, acousto-optic frequency shift, and nonreciprocal light propagation. [16,17,26,27] Different from the intrinsic optomechanical interactions in waveguides, [28][29][30][31][32][33][34] it is unnecessary to design suspended waveguides or optomechanical cavities for the AO interactions, which guarantees the stability and feasibility for on-chip applications. [16,35] Meanwhile, the electrically driven AO interactions exhibit higher AO scattering efficiency than the intrinsic optomechanical interactions, which can be adjusted in both optical domain and electrical domain. [36,37] Although LN (d 33 = 6 pC N -1 ) is a good candidate in AO interactions for its outstanding optical and piezoelectric properties, [38] it is not compatible with complementary metal-oxide-semiconductor (CMOS) technology to achieve large-scale fabrication. [20][21][22] As for AlN, it is generally deposited on silicon substrate through magnetic sputtering that is compatible with CMOS technology, but it poses a challenge to design waveguide structures in AlN layer because of the smaller refractive index than silicon substrate. [17,18] Therefore, suspended waveguide structures are indispensable for AlN on silicon substrate to carry out AO interactions. Surprisingly, a nonsuspended structure of AlN deposited on silicon-on-insulator (SOI) platform with a SiO 2 interlayer had realized AO modulation recently, where the optical wave is mostly confined in the nonpiezoelectric silicon layer instead of AlN layer. [39] In that structure, the SAW actuated by the IDT propagates from AlN layer across SiO 2 interlayer and finally modulates the optical waves in the silicon waveguides, where the SiO 2 interlayer greatly increases the SAW propagation loss and degrades the acoustic performances. [40] At last, with the same CMOS-compatible deposition as AlN and better piezoelectric properties than AlN, Aluminum scandium nitride (AlScN) has attracted extensive attention for its excellent piezoelectric properties in the micro-electromechanical system applications. In this work, AlScN is demonstrated to be a promising candidate for on-chip acousto-optic coupling interactions with outstanding piezoelectric properties as well. Based on piezoelectric Al 0.6 Sc 0.4 N film deposited on silicon-on-insulator platform, the proposed devices exhibit impressive acousto-optic coupling performances over a short interaction length of 210 µm with surface acoustic waves actuated by interdigital transducers. Meanwhile, the acousto-optic coupling...

show abstract

“…Tuning these sputter parameters allows one to optimize the film microstructure and morphology as well as the stress to meet device design requirements. , Additionally, the typical growth temperature of sputter deposition is below 400 °C, satisfying the requirement of the CMOS process. Moreover, the performance of AlScN-based thin film acoustic wave devices has been extensively evaluated. − For example, Wang et al reported that Al 0.88 Sc 0.12 N-based laterally coupled alternating thickness (LCAT) mode resonators operate at above 3 GHz with an enhanced effective coupling coefficient ( k eff 2 ) of 12.1%, showing that a higher bandwidth can be achieved by using AlScN . More recently, Fichtner et al reported the ferroelectric properties of AlScN in 2019 .…”

Section: Introductionmentioning

confidence: 99%

Scandium-Doped Aluminum Nitride for Acoustic Wave Resonators, Filters, and Ferroelectric Memory Applications

Chen

Liu

et al. 2022

ACS Appl. Electron. Mater.

View full text Add to dashboard Cite

Scandium-doped aluminum nitride (AlScN) has generated great research interest owing to its unique properties. The wurtzite-structure AlScN is compatible with the complementary metal oxide semiconductor (CMOS) process and has improved piezoelectricity compared with undoped aluminum nitride (AlN), making it a promising candidate to be used for next-generation radio frequency (RF) microelectromechanical system (MEMS) building blocks. Additionally, the ferroelectricity observed in AlScN can be potentially applied to ferroelectric memory devices. In this spotlight article, we provide a brief introduction of AlScN and summarize the recent progress of AlScN-based applications, including RF acoustic wave resonators, filters, and ferroelectric memory devices. Finally, the current challenges as well as the future opportunities of AlScN materials and related applications are discussed.

show abstract

High-Overtone Thin Film Ferroelectric AlScN-on-Silicon Composite Resonators

Cited by 29 publications

References 27 publications

X–Ka Band Epitaxial ScAlN/AlN/NbN/SiC High-Overtone Bulk Acoustic Resonators

X–Ka Band Epitaxial ScAlN/AlN/NbN/SiC High-Overtone Bulk Acoustic Resonators

Acousto‐Optic Modulation in Silicon Waveguides Based on Piezoelectric Aluminum Scandium Nitride Film

Scandium-Doped Aluminum Nitride for Acoustic Wave Resonators, Filters, and Ferroelectric Memory Applications

Contact Info

Product

Resources

About