Surface smoothing induced by epitaxial Si capping of rough and strained Ge or Si1−xGex morphologies: a RHEED and TEM study
作者： D. Dentel , J.L. Bischoff , L. Kubler , J. Werckmann , M. Romeo
DOI: 10.1016/S0022-0248(98)00354-6
关键词:
摘要: The same Si/Ge/Si or Si/Si1−xGex/Si structures grown at 400°C on Si(0 0 1) are compared, either in real time by reflection high-energy electron diffraction (RHEED) the final product transmission microscopy (TEM). This allows us to follow interface morphology variations during Si re-growth upon Ge containing layers of various thicknesses alloy x fractions. As shown passage from spotty streaky RHEED patterns and specular beam intensity oscillation evolutions, surfaces roughen systematically strained Si1−xGex (SiGe) growth smooth rapidly subsequent 4 6 monolayers, least elastic hut-clustering islanding range with {1 5} facets. With help TEM examinations, a coherent picture may be proposed for these surface smoothing observations: (i) A dominant mechanism form quick diffusion occurring initially Ge-strained surfaces. It ensures heteregeneous accumulation towards places minimized misfit, i.e., troughs SiGe morphologies. (ii) slower (as occuring Si) depleting emerging island crests contributing an overall termination (Ge segregation) complementary smoothing. latter mechanism, only important low kinetics, favours formation alloyed interfaces as by-product lateral intermixing. At high kinetics former prevails leading better preserved morphologies appearing chemically more abrupt but less flat.
harvard.edu
elsevier.com
sci-hub.se 参考文章(31)
Y.-W. Mo, J. Kleiner, M.B. Webb, M.G. Lagally, Surface self-diffusion of Si on Si(001) Surface Science. ,vol. 268, pp. 275- 295 ,(1992) , 10.1016/0039-6028(92)90968-C
Albert-László Barabási, Self-assembled island formation in heteroepitaxial growth Applied Physics Letters. ,vol. 70, pp. 2565- 2567 ,(1997) , 10.1063/1.118920
A. A. Williams, J. M. C. Thornton, J. E. Macdonald, R. G. van Silfhout, J. F. van der Veen, M. S. Finney, A. D. Johnson, C. Norris, Strain relaxation during the initial stages of growth in Ge/Si(001) Physical Review B. ,vol. 43, pp. 5001- 5011 ,(1991) , 10.1103/PHYSREVB.43.5001
S. S. Iyer, J. C. Tsang, M. W. Copel, P. R. Pukite, R. M. Tromp, Growth temperature dependence of interfacial abruptness in Si/Ge heteroepitaxy studied by Raman spectroscopy and medium energy ion scattering Applied Physics Letters. ,vol. 54, pp. 219- 221 ,(1989) , 10.1063/1.101014
Kazushi Miki, Kunihiro Sakamoto, Tsunenori Sakamoto, Hajime Okumura, Naoki Takahashi, Sadafumi Yoshida, Gem/Sin strained-layer superlattices fabricated by phase-locked epitaxy Journal of Crystal Growth. ,vol. 95, pp. 444- 446 ,(1989) , 10.1016/0022-0248(89)90438-7
A.J. Pidduck, D.J. Robbins, A.G. Cullis, W.Y. Leong, A.M. Pitt, Evolution of surface morphology and strain during SiGe epitaxy Thin Solid Films. ,vol. 222, pp. 78- 84 ,(1992) , 10.1016/0040-6090(92)90042-A
N. Ohtani, S.M. Mokler, M.H. Xie, J. Zhang, B.A. Joyce, RHEED investigation of Ge surface segregation during gas source MBE of Si Si1 - xGex heterostructures Surface Science. ,vol. 284, pp. 305- 314 ,(1993) , 10.1016/0039-6028(93)90501-A
C.M. Aldao, J.L. Iguain, H.O. Mártin, A steady-state approach to determine diffusion coefficients : the migration of silicon on the Si(100) surface Surface Science. ,vol. 366, pp. 483- 490 ,(1996) , 10.1016/0039-6028(96)00828-X
F. K. LeGoues, M. Copel, R. M. Tromp, Microstructure and strain relief of Ge films grown layer by layer on Si(001). Physical Review B. ,vol. 42, pp. 11690- 11700 ,(1990) , 10.1103/PHYSREVB.42.11690
D. J. Godbey, M. G. Ancona, Ge profile from the growth of SiGe buried layers by molecular beam epitaxy Applied Physics Letters. ,vol. 61, pp. 2217- 2219 ,(1992) , 10.1063/1.108272