The cracking of Czochralski-grown crystals

Growth of Sillenite-Structure Single Crystals

“…Faceting at low pull rates is characteristic of incongruently melting compounds, such as BTO, BGaO, and BZnO. In the crystal growth of the congruently melting compounds BSO and BGO at low thermal gradients (<40°C/cm) and pull rates below 2.5 mm/h, the crystal-melt inter- Maximum permissible axial temperature gradient as a function of crystal radius [36]. face is also faceted [28], but conditions for nearly isotropic growth can readily be ensured.…”

“…For example, the maximum gradient for crystals 1 cm in radius is Ӎ50°C/cm, and the theoretically predicted value is Ӎ76°C/cm. The maximum cooling rate of bismuth silicate crystals after the growth process is 64/R 2 (°C/h) at their melting point and a factor of 2 slower near room temperature [36]. The rotational instability of bismuth-containing oxide melts in BSO and BGO crystal growth was investigated in [38,40,44,48,57,58,60].…”

“…The maximum pull rate depends on the melt composition, crystal size, and temperature gradients over the melt [36,38]. Brice [36] analyzed the axial and radial temperature gradients for isotropic growth of bismuth silicate single crystals.…”

“…Brice [36] analyzed the axial and radial temperature gradients for isotropic growth of bismuth silicate single crystals. According to his results, the maximum axial temperature gradient for crystals up to 50 mm in diameter is given by where is the axial temperature gradient over the melt and R is the crystal radius (cm).…”

Optimization of the cooling profile to achieve crack-free Yb:S-FAP crystals

“…Brice [9] examined thermal strain in the crystal during growth and cooling, and obtained the analytical solution for the maximum allowed cooling rate. Related to the maximum cooling rate, there exists a critical radial temperature difference between the center and the edge of the crystal above which the crystal will crack.…”