Precise Thermal Expansion Measurements of Single Crystal Silicon with an Interferometric Dilatometer

摘要

Silicon is one of the most important reference materials for various thermophysical properties, such as thermal expansivity, specific heat capacity, thermal diffusivity thermal conductivity, and emissivity. Silicon can be manufactured as a large size high-purity dislocation-free single crystal which introduces stability. uniformity and universality with its physical properties. We have been developing an interferometric dilatometer operated at room temperature. The dilatometer comprises a double path intefferometer that utilizes an optical heterodyne technique and a compact vacuum thermal bath. controlled by a thermoelectric transducer, which enables both accurate and efficient measurements. In this paper, the linear thermal expansion coefficient (LTEC) of two silicon single-crystals oriented in the [110] and [100] directions over the temperature range between 0 and 50℃ was measured. The results for the thermal expansion coefficient of these two directions coincide with each other to within 0.4 × 10~(-8) K~(-1). The present data also show very good agreement with the CODATA recommended data to within 0.2 × 10~(-8) K~(-1) over the whole measured temperature range.