Temperature Compensation with AlN Film on Y-128° LiNbO₃

Abstract

Y-128° LiNbO3 is a well-known high-electromechanical-coupling Surface Acoustic Wave (SAW) material, but its usefulness is limited because of its poor temperature-stablility property. AlN films have some excellent characteristics, such as high SAW velocity, stable chemical properties, and high-temperature stability. In this research, the c-axis-oriented AlN films were successfully prepared on Y-128° LiNbO3 by the sputtering method and a SAW delay line oscillator under various temperatures was used to measure the temperature coefficient of frequency (TCF) value of this structure. For Y-128° LiNbO3 with an AlN layer, the TCF value was from -76.32 (ppm/°C) to -39.04 (ppm/°C) and the improved quantity was 48.8%. The oscillator frequency at 25°C also increased from 40.0909 MHz up to 41.6221 MHz. It exhibited Y-128° LiNbO3 with an AlN layer that will effectively improve the poor temperature stability and enhance the SAW velocity.

Microstructural evolution and formation of highly c-axis-oriented aluminum nitride films by reactively magnetron sputtering deposition

“…Generally, AlN films can be synthesized using several techniques, such as reactive sputtering [4][5][6][7], molecular beam epitaxy [8], laser ablation [9], chemical vapor deposition (CVD) [10,11], and plasma-enhanced CVD [12]. Among these methods, the reactive magnetron sputtering technique is considered to be the favorable selection due to its easily deposited high c-axis orientation and its high growth rate.…”

Lateral magnetic stiffness under different parameters in a high-temperature superconductor levitation system*

“…In addition, the minor loop size has a great effect on the magnetic stiffness. [22][23][24][25] The experimental results reported by Hull and Cansiz revealed that the average magnetic stiffness changed monotonically with the minor loop size. [22] We also simulated the average magnetic stiffness of various laterally or vertically sized minor loops changing from 0.1 mm to 2 mm when the PM moved vertically or horizontally above the HTS.…”

“…[22] We also simulated the average magnetic stiffness of various laterally or vertically sized minor loops changing from 0.1 mm to 2 mm when the PM moved vertically or horizontally above the HTS. [23][24][25] The calculation results demonstrated that most of the average magnetic stiffness values were intensely influenced by the sizes of the minor loops. In order to avoid the errors caused by different sizes of the minor loops, the approximate value of the magnetic stiffness was obtained using the linearly extrapolating to zero traverse method.…”

“…In order to avoid the errors caused by different sizes of the minor loops, the approximate value of the magnetic stiffness was obtained using the linearly extrapolating to zero traverse method. [22][23][24][25] Magnetic stiffness is a main parameter for taking into account the stable levitation. Many researchers devoted effort to finding the methods to enhance the stiffness.…”

Propagation Characteristics of Surface Acoustic Waves in AlN/128° Y–X LiNbO3 Structures

“…Therefore, depositing AlN films on 128°Y LiNbO 3 may provide a new piezoelectric material for SAW devices. Characteristics of sputtering AlN films on 128°Y LiNbO 3 were examined [7] and their SAW properties were measured [8,9]. Highly c-axis-oriented AlN films were achieved via the investigation of X-ray diffraction (XRD) [7].…”