GROWTH OF PIEZOELECTRIC-CRYSTALS BY CZOCHRALSKI METHOD

The Czochralski method is one of the most widely used industrial technique to grow single-crystals, since it applies to a very large range of compounds, such as semiconductors, oxides, fluorides, etc... Many exhibit piezoelectric properties and some of them find applications in Surface-Acoustic-Waves or Bulk-Acoustic-Waves devices. That explains the large amount of work made on the development of the corresponding growth processes and the high levels of production achieved in the world today. We will review the basic principle, main features and parameters of the Czochralski method, and the configuration which is used by Crismatec. Then we will discuss in more details the growth parameters for the two piezoelectric crystals that we are producing, LiNbO3 and LiTaO3, and present the state-of-the-art for both crystals : pulling axis, diameter and quality. We will also discuss some preliminary results on the growth of the new La3Ga5SiO14 langasite crystal.