ANOMALOUS TEMPERATURE-DEPENDENCE OF LATTICE-CONSTANT IN SILICON-CRYSTALS

The lattice constant of silicon single-crystals grown with the floating-zone and the Czochralski methods have been measured as a function of temperature by means of a high-angle double-crystal X-ray diffractometer with a relative accuracy of 1 part in 107. Anomalous temperature dependence and anomalous increase in Bragg peak widths are observed around 200 K only when the measurement is made with lowering temperature. The anomaly diminishes when thermal cycles between 300 and 100 K are repeated, though it is still appreciable at the third cycle. © 1979, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.