Nano Pattern Formation and Surface Modifications by Ion Irradiation

Abstract

Ion Irradiation is a technologically important technique to modify the surfaces. We have investigated the patterning of InP(111) surfaces by low energy (3 keV) as well as high energy (1.5 Mev) ion beams. After low energy ion irradiation, surfaces exhibit well defined nano dots which ripen at initial stages but exhibit fragmentations at high fluences. The surface rms, at both the energies, displays a similar behaviour of initially increasing with increasing fluences but decreasing for higher fluences. The studies show some common features at these low and high energies, like the smoothening of surface beyond the a/c transition.

Nanoscale structural defects in oblique Ar+ sputtered Si(111) surfaces

“…Raman scattering is a potential characterization technique for the distinction of crystalline and amorphous phases in semiconductors by identifying their Raman active lattice modes 25–28 . For silicon, the Raman spectrum is primarily characterized by scattering through Longitudinal Optical (LO) vibrations and Transverse Optical (TO) phonons vibrations corresponding to Brillouin zone center 4,29 . Interestingly for (111) face, scattering by both these modes of brillouin zone center are feasible.…”

“…Interestingly for (111) face, scattering by both these modes of brillouin zone center are feasible. Keeping this in mind, we have explored the structural modifications associated with these LO and TO modes after argon ion irradiation at various oblique incidences 4,28,29 . For Diode pumped laser having incident wavelength of 532 nm, the Raman probing depths are nearly 770 nm and 100 nm in crystalline and amorphous phases of Si(111), respectively 28,29 .…”

“…Although there are several approaches for fabricating such devices, but ion implantation is the best suited technique as it induces the formation of buried amorphous layers with precise interfaces to accentuate different properties of silicon, hence, intensifying possibility of fabricating novel structures 1–3 . The augmented interest in VLSI technology, in turn, brings the usage of ion implantation, predominantly in low energy range, to the forefront 3,4 . This low energy implantation, however, results in severe alterations in the subsurface region of the target matrix crucially depending on the implantation conditions like energy, implantation dose and angle of the incoming ion 2,3 .…”

“…This low energy implantation, however, results in severe alterations in the subsurface region of the target matrix crucially depending on the implantation conditions like energy, implantation dose and angle of the incoming ion 2,3 . Thus, for keV and MeV ion implantation to be key engineering tool in the development of semiconductor industry 4 , it becomes necessary to address the issue of surface modifications and the factors governing these alterations 1,3 .…”

Topography evolution of 500 keV Ar4+ ion beam irradiated InP(100) surfaces – formation of self-organized In-rich nano-dots and scaling laws

“…Such correlation in the dot size and the surface roughness is also observed on the low energy Ar ion bombarded surfaces. [34][35][36] The nuclear energy losses in InP via elastic collisions by 1.5 keV and 500 keV Ar ions are 26.8 and 27.4 eV Å À1 , respectively. Therefore, the elastic collisions that cause surface coarsening via kinetic sputtering for large time scales are the primary source of such a surface morphology.…”