4 inch langasite crystals grown along SAW-cut orientations

•LGS crystals were possible to saw 4 in. wafer which was grown along the SAW-cut orientations.•The ratio of crystal diameter and crucible diameter must be less than 60%.•The rotation rate should be adapted during growth.•The growth rate must be below the critical growth rate.•The average frequency constant value is 1.34 MHz mm.

Langasite crystal is an important substrate material for intermediate frequency surface acoustic (IF-SAW) wave filters and high temperature sensors, due to their high piezoelectric constants, electromechanical coupling factor and no phase transformation up to the melting point. In this work, 3 and 4 in. circular shaped langasite crystals along SAW-cut orientations (0°, 22°, 90°) and (0°, 138.5°, 26.6°) were grown successfully. Key parameters to grow high quality crystals are discussed. Rocking curve and frequency tests show a high homogeneity of these crystals. Homogeneous langasite crystals grown along a SAW-cut orientation with controlled shape are of enormous commercial value.