CHARACTERIZATION OF DEFECTS IN LI2B4O7 CRYSTALS GROWN BY CZOCHRALSKI AND BRIDGMAN METHODS

Lithium tetraborate (Li2B4O7) has attracted much attention as a surfac e acoustic wave substrate for high-frequency use and its excellent non linear optical properties have been recently found. In the present rep ort, the main crystalline defects observed by X-ray topography in Li2B 4O7 (110) wafers grown by the Bridgman method and by the Czochralski m ethod are presented. The main trends observed are a majority of disloc ations in {112} planes, a minority of dislocations in the {111} planes , and low-angle grain boundaries in both {111} and {112} planes.