Formation of porous germanium layers with various surface morphology in dependence on mass of implanted ions

Abstract The surface morphology of nanoporous Ge (PGe) layers formed by low-energy high-dose implantation with transition metal ions depending on their mass (52Cr+, 55Mn+, 56Fe+, 59Co+, 59Ni+ and 63Cu+) was studied by high-resolution scanning electron microscopy. Ion implantation of single-crystal c-Ge substrates was carried out using similar conditions with an energy of E = 40 keV and a dose of D = 5.0·1016 ion/cm2. Additionally, c-Ge was also implanted with heavier ions 108Ag+ and 122Sb+ at E = 30 keV for comparative experiments on the surface PGe morphology. It was observed that the morphology of the PGe layers changed with increasing mass of the irradiated ion from a labyrinth, hole type, three-dimensional network to spongy structure.