Langasite crystal possesses some excellent properties, such as higher piezoelectric constants and electromechanical coupling factor than quartz, no phase transition from room temperature to their melt point. Furthermore, langasite crystal can be grown by Czochralski method, and commercial three and four inch langasite wafers are available. Therefore, it becomes one of the most competitive candidate materials for high temperature (up to 1000 ^oC) sensors and acoustic electronic devices. However, there ere two issues prevented the large-scale application of langasite crystal, high cost and low homogeneity.

In this work, 4 inches langasite crystals along SAW-cut orientations had been grown successfully. The crystal shows in fig. 1 growth along Euler angles (0º, 22º, 90º) direction, and the crystal shows in fig. 2 growth along Euler angles (0º, 138.5º, 26.7º) direction. The growth morphology of those two types’ as-grown crystals was discussed. The facet growth were compared with the as-grow crystal grown along Z direction. The high resolution X-ray diffraction surface mapping of 14 mm × 14 mm sample was measured. Frequency constant of 4 inches wafer has been tested by ALC-III frequency meter. Finally, resistivity was measured as a function of temperature. The results show that the 4 inches langasite crystals have high homogeneity, can satisfy the requirements of acoustic electronic devices and high temperature effective sensors applications.

Fig. 1 4 inches Langasite crystal growth along Euler angles (0º, 22º, 90º)

Fig. 2 4 inches Langasite crystal growth along Euler angles (0º, 138.5º,26.7º)

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