A determination of the thermal expansion of pure Ge and a measurement of the differential thermal expansion of a GeSingle Bond signGaAs thin-layer couple

The absolute thermal expansion of single-crystal germanium was measured from 25 to 360°C. The fractional change in length determinations have a precision of 1 part in 105. The experimental data agree, within the limits of experimental error, with the results determined for polycrystalline germanium by Kirby. A technique was developed for measuring the differential thermal expansion of a two-layer couple. An upper limit for the differential thermal expansion of an epitaxial germanium layer on a gallium arsenide substrate was determined and the result indicates that the thermal expansion coefficients agree to within 1 part in 108. This result indicates that thermal expansion effects do not contribute to the observed stress in epitaxial layers of germanium on gallium arsenide. © 1972 The American Institute of Physics.