High Potential Columnar Nanocrystalline AlN Films Deposited by RF Reactive Magnetron Sputtering

Han, Chengzhang; Chen, Da; Zhang, Yao-Zhong; Xu, D.; Liu, Yijian; Kong, Eric Siu-Wai; Zhang, Yafei

doi:10.1007/bf03353690

Cited by 22 publications

(9 citation statements)

References 12 publications

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“…We think that this may be due to the low precision of our X-ray diffraction and the low thickness of our AlN top layer. In general, only the AlN films with a thickness of a several hundred nanometers can show obvious AlN peaks [ 20 , 21 , 22 ]. However, the thickness of the AlN film in our work is only about 30 nm.…”

Section: Resultsmentioning

confidence: 99%

Novel AlN/Pt/ZnO Electrode for High Temperature SAW Sensors

et al. 2017

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In order to develop a film electrode for the surface acoustic wave (SAW) devices working in high temperature, harsh environments, novel AlN/Pt/ZnO multilayers were prepared using pulsed laser deposition (PLD) systems on langasite (LGS) substrates. The AlN film was used as a protective layer and the ZnO buffer layer was introduced to improve the crystal quality of Pt films. The results show that the resistances of Pt and AlN/Pt film electrodes violently increase above 600 °C and 800 °C, respectively, while the resistances of AlN/Pt/ZnO electrodes have more stable electrical resistance from room temperature to 1000 °C. The AlN/Pt/ZnO electrode, where the ZnO film was deposited at 600 °C, has the best temperature stability and can steadily work for 4 h at 1000 °C. The mechanism underlying the stable resistance of the AlN/Pt/ZnO electrode at a high temperature was investigated by analyzing the microstructure of the prepared samples. The proposed AlN/Pt/ZnO film electrode has great potential for applications in high temperature SAW sensors.

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Section: Resultsmentioning

confidence: 99%

Novel AlN/Pt/ZnO Electrode for High Temperature SAW Sensors

et al. 2017

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“…The proposed approach for generating dual-frequency ultrasound was established from the unique vibration mode of a PMUT, which strongly depends on the polarization state of its ferroelectric lm. Unlike the proposed technique, conventional driving methods, in which the transducer uses either a nonferroelectric lm (such as aluminium nitride (AlN) [23][24][25] or strongly polarized ferroelectric lm), the transducer operates below the coercive voltage (the voltage required to induce domain reversal). Here, driving with a large bipolar signal above the coercive voltage results in the membrane vibrating at a frequency that is desynchronized from the input voltage.…”

Section: Concepts Of Dual Frequency Generation In Ferroelectric Pmutmentioning

confidence: 99%

Dual-frequency piezoelectric micromachined ultrasound transducer based on polarization switching in ferroelectric thin film

Lee

Park

Jung

et al. 2023

Preprint

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Dual-frequency ultrasound has advantages over conventional ultrasound, which operates at a specific frequency band, due to its additional frequency response. Moreover, a tunable frequency from a single transducer enables sonographers to achieve ultrasound images with a large detection area and high resolution. This facilitates the availability of more advanced techniques that require low- and high frequency ultrasound simultaneously such as harmonic imaging and image-guided therapy. In this article, we present a novel method for dual-frequency ultrasound generation from a ferroelectric piezoelectric micromachined ultrasound transducer (PMUT). Uniformly designed transducer arrays can be used for both deep low-resolution imaging and shallow high-resolution imaging. To switch the ultrasound frequency, the only requirement is to tune a DC bias for controlling the polarization state of the ferroelectric film. Flextensional vibration of the PMUT’s membrane strongly depends on the polarization state, producing low- and high-frequency ultrasound from a single excitation frequency. This strategy for dual-frequency ultrasound dispenses with the requirement for either multi-electrode configurations or hetero-designed elements, which are integrated into an array. Consequently, this technique significantly reduces the design complexity of transducer arrays and their associated driving circuits.

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“…Before the formal fabrication, the process parameters of AlN thin lm were optimized repeatedly to obtain high c-axis orientational quality. 30 The Bragg reector, consisting of titanium (Ti) and tungsten (W) layers, was rst deposited on p-type 3 inch Si (100) substrate with 1-10 U cm resistivity at 25 C, and then a AlN thin lm was deposited on the top of the Bragg reector at 300 C. Lastly, a Au lm was deposited on top of the AlN for the electrodes. The AlN thin lm was obtained by a RF reactive magnetron sputtering system with an Al target in a N 2 and Ar mixture atmosphere.…”

Section: Smr Fabricationmentioning

confidence: 99%