Enhanced strain relaxation of epitaxial SiGe layers on Si(100) after H+ ion implantation

We studied strain relaxation of pseudomorphic Si1-xGex layers on Si(100) af ter hydrogen implantation and thermal annealing. Hydrogen implantation indu ces a narrow; defect band slightly below the SiGe/Si interface giving rise to strongly enhanced strain relaxation of the SiGe epilayer during subseque nt thermal annealing. The hydrogen implanted and annealed samples show a si gnificantly reduced threading dislocation density and a much higher degree of strain relaxation than just thermally relaxed epilayers. We assume that the hydrogen induced defects promote nucleation of dislocation loops which extend to the interface to form strain relieving misfit segments. The sampl es have been investigated by X-ray diffraction. Rutherford backscattering s pectrometry ion channeling and transmission electron microscopy. (C) 1999 E lsevier Science B.V. All rights reserved.