EFFECTS OF H-TERMINATION ON GE FILM GROWTH ON SI(111) SURFACES BY SOLID-PHASE EPITAXY

We have investigated solid phase epitaxy (SPE) of Ge films on H-termin ated Si(111) surfaces using scanning tunneling microscopy (STM). In or der to clarify the influence of adsorbed H atoms on the initial growth of Ge SPE on Si(111) surfaces, sub-bilayer (BL)-thick Ge films on the H-terminated Si surfaces were grown. It has been found that Ge cluste rs are formed at room temperature and the cluster shape changes by the existence of H atoms at the Ge/Si interface due to the reduction of i nteraction between Ge and Si atoms. Moreover, H atoms at the Ge/Si int erface suppress the progress of surface reconstruction of Ge films and the crystallization of Ge films occurs with the desorption of H atoms from the Ge/Si interface. Two-dimensional (2D) islands formed by SPE at 500 degrees C contain twinned domains and have irregular shapes whi le triangular-shaped 2D-islands are formed in Ge epitaxial growth by m olecular beam epitaxy (MBE). The irregular shapes observed in the SPE growth are considered to result from the small surface migration of Ge atoms during annealing. (C) 1998 Elsevier Science B.V. All rights res erved.