Precise measurement of the thermal expansion of silicon near 40 °C

We report absolute measurements of the thermal-expansion coefficient of single-crystal silicon having a precision of ±0.2%. Five thermal-expansion values have been determined using 1.9 °C temperature measurement intervals within the temperature range 34–44 °C. Our value for the thermal expansion of silicon at 35.22±0.08 °C is 2.683±0.005×10−6 cm/cm °C, which agrees with previous measurements by others and represents an almost fivefold increase in accuracy.