OBSERVATION OF MICRODEFECTS IN AS-GROWN CZOCHRALSKI SILICON-CRYSTALS BY SYNCHROTRON-RADIATION TOPOGRAPHY

Microdefects in as-grown Czochralski silicon crystals have been invest igated by means of X-ray topography using 60 keV radiation from a sync hrotron radiation source. In crystals grown at the pulling rate of 0.4 mm/min, very fine defects were observed and their density was about 1 x 10(3)/cm3, which was in agreement with the result obtained by the f low pattern technique using Secco preferential etching. The strain fie ld of the defects was analyzed from the topographic image height of de fects using the kinematical diffraction theory. The values of the defe ct strength that gave a measure of the size of the defects were from 2 to 40 x 10(-20) m3.