Crystallographic Texture of Submicron Thin Aluminum Nitride Films on Molybdenum Electrode for Suspended Micro and Nanosystems

Sah, R. E.; Kirste, Lutz; Kirmse, Holm; Mildner, Martin; Wilde, L.; Kopta, Susanne; Knöbber, Fabian; Krieg, M.; Cimalla, V.; Lebedev, V.; Ambacher, O.

doi:10.1149/2.001305jss

Cited by 3 publications

(2 citation statements)

References 40 publications

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“…This phenomenon should be explained only by the significant structural enhancements in the AlN film. For the case of AlN/Mo/AlN structures, these are the increased domain size and improved c-axis orientation of AlN columns grown on a highly oriented Mo interlayer (figure 4(a)), [25] which lead to an increase in the Q in-air value of up to 180-200.…”

Section: Discussionmentioning

confidence: 99%

Enhanced mechanical performance of AlN/nanodiamond micro-resonators

Heidrich¹,

Iankov²,

Hees³

et al. 2013

J. Micromech. Microeng.

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Micro electromechanical systems are a matter of intense research pursuing to replace silicon and III–V semiconductor-based components in prospective radio frequency communication devices. Due to their unique material properties, microstructures combining doped nano-crystalline diamond (NCD) and AlN thin films are promising for piezo-actuated microsystems in order to increase operating frequencies. In this work, single and doubly clamped unimorph NCD-on-AlN micro-resonators were fabricated and then characterized by laser vibrometry towards their flexural resonant frequencies in the range of 0.1–20 MHz to deduce their mechanical properties. Enhancements in the structural properties of an AlN piezo-actuator united with an advanced elasticity of nano-diamond electrode lead to superior mechanical parameters of the resulting unimorphs. These allow for the fabrication of flexural resonant microsystems with a potential to extend the operating frequencies well above 1 GHz.

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Section: Discussionmentioning

confidence: 99%

Enhanced mechanical performance of AlN/nanodiamond micro-resonators

Heidrich¹,

Iankov²,

Hees³

et al. 2013

J. Micromech. Microeng.

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“…Even though Au and Pt have poor adhesion with Si, a thin layer of a suitable material is needed to overcome the etch out problems, but Pt has an additional advantage of large acoustic impedance value that helps to confine the acoustic waves within AlN stack between the electrodes and thus providing a large coupling factor in the frequency range of 2–3 GHz . High electrical conductivity, high adhesion strength, low acoustic attenuation, good etching capability and low value of thermal elastic losses make Mo prominent to use as an electrode …”

Section: Introductionmentioning

confidence: 99%

Influence of metal electrodes on c‐axis orientation of AlN thin films deposited by DC magnetron sputtering

Imran

Yuan

Yin

et al. 2017

Surface & Interface Analysis

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Nanocrystalline aluminum nitride (AlN) thin films were deposited on two types of metallic seed layers on silicon substrates, (111) textured Pt and (110) Mo, by reactive DC magnetron sputtering at low temperature (200°C). Both textured films of Pt and Mo promote nucleation, thereby improving the crystallinity and epitaxial growth condition for AlN thin films. The deposited films were examined by X-ray diffraction, scanning electron microscopy and atomic force microscopy techniques. The results indicated that the preferred orientation of crystallites greatly depends upon the kinetic energy of the sputtered species (target power) and seed layers used. Furthermore, AlN thin films with c-axis perpendicular to the substrate grew on both types of metal electrodes at all power levels larger than 100 W. By comparing the structural properties and compressive stresses at perfect c-axis orientation conditions, it is evident that AlN films deposited on (110) oriented Mo substrates exhibited superior properties as compared with Pt/Ti seed layers. Furthermore, less values of compressive stresses (À3 GPa) as compared with Pt/Ti substrates (À7.08 GPa) make Mo preferentially better candidate to be employed in the field of suspended Micro/Nano -electromechanical systems (MEMS/NEMS) for piezoelectric devices.

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Structural and electrical properties of fiber textured and epitaxial molybdenum thin films prepared by magnetron sputter epitaxy

Sundarapandian,

Raghuwanshi,

Straňák

et al. 2025

Applied Physics Letters

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Molybdenum (Mo) due to its optimal structural, physical, and acoustic properties finds application as electrode material in aluminum scandium nitride and aluminum nitride (AlN) based bulk acoustic wave (BAW) resonators. Epitaxial Mo thin films exhibiting low resistivity can improve the performance of the BAW resonator by enhancing both the electro-mechanical coupling coefficient (keff2) and quality factor Q. In this study, we systematically vary the growth temperature of Mo grown on fiber-textured and epitaxial wurtzite-aluminum nitride (AlN) to study the changes in structural and electrical properties of the Mo films. Results show that Mo grown at 700 °C on epitaxial AlN exhibits low surface roughness (Rq = 0.8 nm), large average grain diameter (dgrain = 330 nm), low resistivity (ρ=6.6 ± 0.06 μΩ cm), and high crystal quality (XRD Mo 110 ω-FWHM = 0.63°). XRD pole figure and ϕ-scan analysis reveal that irrespective of the growth temperature, Mo is fiber textured on fiber-textured AlN and has three rotational domains on epitaxial AlN. This study shows that the resistivity of Mo reduces with increasing growth temperature, which we relate to increasing average grain diameter. Additionally, we show that fiber-textured Mo has more high angle grain boundaries resulting in consistently higher resistivity than its epitaxial equivalent.

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Crystallographic Texture of Submicron Thin Aluminum Nitride Films on Molybdenum Electrode for Suspended Micro and Nanosystems

Cited by 3 publications

References 40 publications

Enhanced mechanical performance of AlN/nanodiamond micro-resonators

Enhanced mechanical performance of AlN/nanodiamond micro-resonators

Influence of metal electrodes on c‐axis orientation of AlN thin films deposited by DC magnetron sputtering

Structural and electrical properties of fiber textured and epitaxial molybdenum thin films prepared by magnetron sputter epitaxy

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