Medium energy ion irradiation of Ge surface - search for a better understanding of the surface nano-patterning

Abstract

aWe report the morphological changes on Ge surfaces upon 50 keV Ar + and 100 keV Kr + beam irradiation at 60°angle of incidence. The Ge surfaces having three different amorphous-crystalline (a/c) interfaces achieved by the pre-irradiation of 50 keV Ar + beam at 0°, 30°and 60°with a constant fluence of 5 × 10 16 ions/cm 2 were further processed by the same beam at higher fluences viz. 3 × 10 17 , 5 × 10 17 , 7 × 10 17 and 9 × 10 17 ions/cm 2 to understand the mechanism of nano-scale surface patterning. The Kr + beam irradiation was carried out only on three fresh Ge surfaces with ion fluences of 3 × 10 17 , 5 × 10 17 and 9 × 10 17 ions/cm 2 to compare the influence of projectile mass on surface patterning. Irrespective of the depth of a/c interface, the nanoscale surface patterning was completely missing on Ge surface with Ar + beam irradiation. However, the surface patterning was evidenced upon Kr + beam irradiation with similar ion fluences. The wavelength and the amplitude of the ripples were found to increase with increasing ion fluence. In the paper, the mass redistribution at a/c interface, the incompressible solid flow through amorphous layer, the angular distribution of sputtering/backscattering yields and the generation of non-uniform stress across the amorphous layer are discussed, particularly in analogy with low energy experiments, to get better understanding of the mechanism of nanoscale surface patterning by the ion beams.

100 keV H+ ion irradiation of as‐deposited Al‐doped ZnO thin films: An interest in tailoring surface morphology for sensor applications

“…With understanding of the experimental results based on various ion‐target parameters, new theories evolved time to time . Recent experiments show that periodic nanostructures on bulk Si surface can be formed by generating an amorphous‐crystalline ( a / c ) interface and incompressible solid flow across top amorphous is believed to be the cause of surface morphological changes with periodic nanostructures . The evolution of the morphology on the ion bombarded surfaces is finally governed by the balance between multiple roughening and smoothening processes.…”

Surface nanopatterning by ion beam irradiation: compositional effects

“…Both images in figure 18 also show a characteristic feature of surfaces irradiated with ion beams, namely the development of a saw-tooth surface profile along the projected ion beam direction. This morphology is also produced without foreign atom co-deposition, on different targets such as Si [152][153][154][155][156], Ge [12,[157][158][159], fused silica [160], mica [83,161], carbon [162,163] and aluminium [164]. This morphology appears under prolonged irradiation conditions, being enhanced at large ion beam incidence angles.…”

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

“…[1][2][3] The bombardment of solid surfaces with low energy ions is a very effective approach for the generation of self-organized nanostructures such as nano-dots and nano-ripples. [4][5][6][7][8][9] The very early observations on the formation of the hexagonal and the square nano-dots were reported by Navez et al 10 Based on Sigmund's theory of sputtering 11 and with the help of a linear equation, the morphological evolution of the eroded surfaces was proposed successfully by Bradley and Harper in 1988. 12 However, this linear theory could not explain a number of the experimental observations, such as the saturation/coarsening of the ripple amplitude 13 or the appearance of the kinetic roughening and the formation of the nano-dots on the surface.…”