Hydrogen effects on heteroepitaxial growth of Ge films on Si(111) surfaces by solid phase epitaxy

The influences of hydrogen atoms on Ge heteroepitaxial growth on Si(111) surfaces using solid phase epitaxy (SPE) have been investigated by scanning tunneling microscopy (STM). In the SPE growth of Ge films on H-terminated Si(111) surfaces, the formation of 3-dimensional (3D) Ge islands are suppressed. With the desorption of H atoms, the 3D islands appear on the Ge surface, which are considered to be formed by the agglomeration of Ge atoms. The density of the islands is decreased and the size of the islands is increased by the existence of Si-H bonding at the Ge/Si interface. These phenomena are considered to be caused by the release of the stress in the Ge film and the weakening of the interaction between the Ge film and the Si substrate by Si-H bonding. In addition, the activation energy of the migration of Ge atoms during the agglomeration is determined to be 0.3 eV. © 1998 Publication Board, Japanese Journal of Applied Physics.