STUDY OF THE LOCAL DEFECT STRUCTURE OF CDTE-GE CRYSTALS BY MICROINDENTATION

This paper demonstrates the effectiveness of the microindentation meth od as a way to monitor the quality of cadmium telluride crystals. Meas urements of microhardness and the length of dislocation rays from the rosette around the indentation pit can clearly identify nonuniform dis tributions of structural defects, both along the direction of growth a nd along a diameter of a CdTe boule. The mobility of a dislocations is more sensitive to nonuniformities in the structure than the mobility of beta dislocations and the microhardness. A qualitative corresponden ce is established between the microplasticity characteristics of CdTe: Ge and its germanium content: the hardness of the crystal is insensiti ve to changes in the Ge content in the range from 3X10(16) to 1X10(17) at/cm(3), but increases sharply beginning at a concentration of simil ar to 1x10(17) at/cm(3). The correlation between the value of the micr ohardness and the length of the dislocation rays from the rosette arou nd the imprint of the indentor are analyzed. An estimate is obtained f or the hardness of pure CdTe. (C) 1998 American Institute of Physics.