Determination of internal strain tensors by energy-dispersive X-ray diffraction: Results for Si using the 006 forbidden reflection

Abstract

The internal strain tensor of crystals having the diamond structure has a single independent component {\bar A}. A value {\bar A} = −0.18±0.01 for silicon has been found by observing the 006 forbidden reflection whilst applying a stress along the [1{\bar 1}0] axis. An energy-dispersive method was used so that advantage could be taken of the simultaneous presence of strong reflections (004 and 008) to align the sample with precision and to normalize the intensity measurements. In the course of investigation it was found that the strong reflections increased in intensity as a function of stress, suggesting that the crystal was undergoing a reversible change from the ideally perfect to the ideally imperfect state.