EFFECT OF IMPURITY SEGREGATION ON CRYSTAL MORPHOLOGY OF Y-BAR SYNTHETIC QUARTZ

The effects of Al and H impurities on the crystal morphology of Y-bar synthetic quartz were studied. The growth velocities perpendicular to the Y-axis were evaluated in relation to the Al and H impurity segregations on the growth interfaces. It was found that the -X-growth region has the highest H content and shows the lowest growth velocity, due to the effect of H2O adsorbed on the growth interface in hydrothermal solution. Therefore, the -X-face, (bar1;bar1;20), always becomes larger in size. Al has a selective effect on the (11bar2;2) and (bar1;bar1;2bar2;) faces to suppress the growth velocities and thus is important for crystal morphology. The growth velocities perpendicular to these faces, however, are controllable by the Al impurity content in the nutrient. © 1990 The Japan Society of Applied Physics.