PRODUCTION OF OXIDE PIEZOELECTRIC SINGLE CRYSTAL

摘要

PROBLEM TO BE SOLVED: To eliminate detect, e.g. internally trapped matter, growth strain or twin, by setting such temperature gradient as a container containing a solution has a locally lowered bottom temperature and generating a nucleus of single crystal in the orientation <100> at a bottom thereby growing a single crystal in the orientation <100>. SOLUTION: A platinum container 3 is suspended in a vertical tubular electric furnace 1 where an average temperature gradient of 1 deg.C/mm is set in the vertical direction by means of a heater 2 split vertically into four sections. When the temperature rises, flux and material contained in the container 3 are dissolved and the solution 4 is conditioned. The platinum container 3 is then lowered from the central part of electric furnace 1 toward a lower temperature gradient part and cooled down to the room temperature. Consequently, the nucleus of single crystal is generated in the orientation <100> at a bottom and a single crystal is grown in the orientation <100>. According to the method, a uniform oxide piezoelectric single crystal having no detect, e.g. internally trapped matter, growth strain or twin, exhibiting excellent piezoelectric characteristics and dielectric characteristics even for large area can be produced while suppressing the compositional fluctuation in the crystal significantly.