Correlation between structural properties of AlN/Sapphire and performances of SAW devices in wide temperature range

Aissa, K. Ait; Elmazria, O.; Boulet, Pascal; Aubert, Thierry

doi:10.1109/ultsym.2014.0095

Cited by 2 publications

(3 citation statements)

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“…Hence, from Table 2 , there is a tendency that the c lattice constant of the AlN film increased as a result of annealing. This was probably caused by a relaxation of the compressive stresses that existed in the as-deposited sample [ 12 ] and where the addition of thermal energy shifted the atomic bonds to a lower energy state, thus increasing the c lattice parameter and the film thickness [ 5 ].…”

Section: Discussionmentioning

confidence: 99%

“…Aluminum nitride (AlN) is a piezoelectric material that possesses a wide bandgap (6.2 eV), high thermal conductivity [ 1 ], one of the highest surface acoustic wave (SAW) velocities of 5760 m/s [ 2 ], low electromechanical conversion energy loss, high mechanical strength, ultraviolet transmittance, and high-temperature stability [ 3 , 4 , 5 ]. These attributes make AlN a great material for use in deep-ultraviolet light-emitting diodes (UV-LEDs), laser diodes (LDs), ultraviolet detectors, high-performance SAW devices [ 4 , 6 ], and signal filters [ 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

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Improved Crystallinity of Annealed 0002 AlN Films on Sapphire Substrate

et al. 2023

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AlN is a piezoelectric material used in telecommunication applications due to its high surface acoustic wave (SAW) velocity, stability, and mechanical strength. Its performance is linked to film quality, and one method to achieve high-quality films goes through the process of annealing. Consequently, c-orientated AlN film with a thickness of 1.1 μm deposited on sapphire was annealed at temperatures of 1100 °C and 1150 °C in a N2 controlled atmosphere. This was compared to annealing at 1100 °C, 1450 °C, and 1700 °C with N2 flow in an open atmosphere environment. Sample rotation studies revealed a significant impact on the ⍵-2θ X-ray rocking curve. A slight variation in the film crystallinity across the wafer was observed. After the annealing, it was found that the lattice parameter c was increased by up to 2%, whereas the screw dislocation density dropped from 3.31 × 1010 to 0.478 × 1010 cm−2, and the full width at half maximum (FWHM) of reflection (0002) was reduced from 1.16° to 0.41° at 1450 °C. It was shown that annealing in a N2-controlled atmosphere plays a major role in reducing the oxidation of the AlN film, which is important for acoustic wave devices where the electrodes are placed directly on the piezoelectric substrate. The face-to-face arrangement of the samples could further reduce this oxidation effect.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved Crystallinity of Annealed 0002 AlN Films on Sapphire Substrate

et al. 2023

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“…These deviations are in fact very valuable because obtained data provide us with the possibility to characterize the thickness dependence of the AlN averaged elastic properties and to get deeper understanding of the properties of the experimentally obtained materials. The optimized AlN deposition regimes were used for obtaining AlN/Sapphire high quality structures [18,19]. …”

Section: Study Of a Thick Layer Deposition Processmentioning

confidence: 99%