Surface morphology of Mn+ implanted Ge(100): A systematic investigation as a function of the implantation substrate temperature

Ge (100) wafers were implanted with 100 keV Mn+ ions with a dose of 2 x 10(16) ions/cm(2) at different temperatures, ranging from 300 to 573 K. The surface morphology of implanted samples, analyzed with scanning electron microscopy and atomic force microscopy measurements, reveals for the 300-463 K implant temperature range the formation of a surface swelled and porous film, containing sponge-like structures. On the contrary, samples implanted in the 513-573 K temperature range present an atomically flat surface, with a roughness less than 1 nm, indicating that crystalline order has been preserved. X-ray photoemission spectroscopy depth profiling measurements indicate the presence of adsorbed oxygen in the porous layer of lower-temperature implanted samples, as well the presence of a large Mn concentration below the expected end of range for impinging ions. Mn and 0 concentrations at anomalously great depths are maximum in the 413 K implanted sample, indicating that the phenomenon of ion beam induced porosity is best favored at a well defined temperature. (C) 2006 Elsevier B.V. All rights reserved.