Simultaneous Determination of the Lattice Constant and Elastics Strain in Cubic Single Crystal

Abstract

In epitaxial single crystal growing it happens very often that the composition of the grown film, say AxB1-x C, is not known exactly. Usually it would be possible to find out that compositions imply by determining the lattice constants of the film. The problem of such a measurement lies in the fact of internal and unknown stresses in the film. On the other side the knowledge of the state of stress σ and strain ε can also be of great importance. To calculate the stresses from X- ray measurements we need the lattice constants in the unstrained condition.Hornstra and Bartels have shown that the lattice constant can be det ermined by X-ray measurements if the strain is isotropic in the film plane. In the following we show that the lattice constant and the full strain tensor can be calculated fromat least four X- ray measurements also in the general case.