Thermal expansion of silicon at temperatures up to 1100 °C

Thermal expansion of CVD single crystal silicon was measured with a push-rod dilatometer up to 1100 °C for different crystallographic orientations of the specimen. Thermal analysis, Laue analysis and X-ray diffraction were used to verify silicon crystal orientation and absence of possible phase transformations. Coefficients of technical thermal expansion have been calculated in this temperature range and their variations with temperature have been demonstrated. These differences might cause anisotropy in thermal stresses, which has been calculated and compared with experimental values of dry-oxidised silicon wafers.