PREDICTABILITY OF PLASTIC RELAXATION IN METAMORPHIC EPITAXY

Theoretical model and experimental data on plastic relaxation are revi ewed. It is concluded that neither equilibrium nor kinetic effects are responsible for the relaxation observed under conditions of high grow th quality in III-V epitaxy; instead dislocation multiplication mechan isms and the space they require to operate constitute the determining factor. Residual strain is then given by epsilon(h) = (0.8 +/- 0.1 nm) /h for a layer of thickness h. Deviations from this rule are indicativ e of poor crystallinity. Silicon-germanium and II-VI materials are bri efly discussed. (C) 1996 The Institute of Materials.