A STUDY OF ION-BOMBARDED NANOSTRUCTURES ON GERMANIUM SURFACES BY SCANNING PROBE MICROSCOPY

Ion bombardment modification of solid surfaces has long been academic and technological interest. Epi-ready Ge (111) and (100) surfaces were implanted with 40 to 200 keV germanium (Ge), cobalt (Co), and iron (F e) ions at the dose of 10(15) to 5 x 10(17) ions/cm(2). Cellular nanos tructures were observed by scanning probe microscopy (SPM), including scanning tunnelling microscopy (STM), and contact-mode and tapping-mod e atomic force microscopy (AFM). These structures are similar (at high er resolution) to those reported in earlier scanning electron microsco pe (SEM) measurements (I.H. Wilson, J. Appl. Phys., 53 (1982) 1698). I n the case of Go-implanted Ge(111), the variation of the root-mean-squ are roughness (R-q) with ion dose (10(16) to 10(17) ions/cm(2)), accel erating voltage (40 to 70 kV) and mean beam current density (15 to 150 mu A/cm(2)) is presented and explained in terms of ion range and surf ace temperature. Finally, the effect of the tip shape in the AFM image s presented in this paper is discussed. (C) 1997 Elsevier Science S.A.