Removal of Stress Hillocks from Platinum-Alumina Electrodes Used in High-temperature SAW Devices

Optimization of SAW Devices with LGS/Pt Structure for Sensing Temperature

“…The pulse signal excitation was conducted by the time domain function of the network analyzer. The response waveform of the proposed device in frequency domain and time domain was measured and RC was then evaluated by using Equations (6) and (7). Next, the RC of the Pt electrodes on LGS was extracted experimentally by characterizing the SAW device with a strategic delay line pattern as described in Figure 2.…”

“…As a typical piezoelectric crystal for high-temperature sensors, langasite (La3Ga5SiO14, LGS) attracts widespread attention because of its excellent acoustic properties at high temperature, which exceed 800 °C [1][2][3][4]. Employing LGS and heat-resistant metal electrodes as platinum (Pt) with large melting point, LGS-based SAW devices were reported frequently for sensing strain, pressure, and even gases at extreme high temperature [5][6][7][8][9][10][11]. Al2O3 was always chosen as a protective layer to improve the stability of LGS/Pt structure.…”

Resonance properties of shear-horizontal surface acoustic waves on Ca3TaGa3Si2O14 at room and high temperatures

“…The measurement results of SAW devices at high temperatures are also reported. [9][10][11] In the past two decades, langasite-type single crystals, such as La 3 Ga 5 SiO 14 (LGS), have received attention as an attractive material for devices with Rayleigh-type SAW due to their excellent temperature coefficient of frequency (TCF) and approximately three times larger electromechanical coupling factor (K 2 ) than that of quartz. One of the authors, Kakio and coworkers have found that a shear-horizontal (SH) SAW with K 2 of approximately 1% and zero TCF can be obtained by forming an IDT using high-density thin film, such as that of gold (Au), on a rotated Y-cut 90°X propagating LGS [Euler angle: (0°, θ, 90°)].…”