First principles calculations of the growth of Si on Ge(001) using As as surfactant

We have performed first principles total energy calculations to investigate the role of As as surfactant in the growth of Si on Ge(001). Ge has a lower surface free energy than Si and, therefore, the preferred growth mode of Si on a Ge surface is to form islands. However, it has been shown experimentally that the deposit of one layer of As on the Ge(001) surface can help in the fabrication of thick, low-defect films of Si. Our calculations show that indeed the presence of a terminating As layer modifies the growth mode, promoting epitaxial growth of Si on Ge(001). We also found that another advantage of the capping As layer is to reduce greatly the possibility of Si and Ge intermixing. (C) 1999 Elsevier Science B.V. All rights reserved.