MECHANISMS OF STRIATIONS FORMATON DURING GROWTH OF KDP FAMILY CRYSTALS. I.L. Smolsky, A.E. Voloshin, E.B. Rudneva, Institute of Crystallography of Russian Academy of Sciences

Usually the striations are considered as a result of inhomogeneous impurity distribution along the growth front due to nonconstancy in the growth conditions (supersaturation, temperature of growth ets). But there are some other reasons related with interior defect structure of crystals or/and surface morphology of the growing faces. In KDP group crystals the growth steps covering faces of the crystal form vicinal hillocks at outcrop points of dislocations or dislocation bunches. It was established [1] that lattice parameters of the crystal depend on growth steps orientation. We are going to discuss:

1.The formation of striations as a result of modification of activity of dislocation steps sources.

2. The striations formation during the steps bunching and macrosteps formation. This process is more active at lower temperatures of crystallization.

3. The striations in rapidly growing crystals in comparison with traditionally grown crystals. This technique uses high level of supersaturation and active stirring of solution.

4. Quantitative X-ray topographic technique for measurements of lattice parameter variations related with striations and homogeneity of crystals.

[1] I.L.Smolsky, N.P.Zaitseva, in:"Growth of Crystals", v.19, ed. by E.I.Givar-

gizov and S.A.Grinberg, Plenum Publ. Corp., N.Y., 1995, p. 173-185.