Effects of Mo seeding on the formation of Si nanodots during low-energy ion bombardment

Abstract

Articles you may be interested inTransition behavior of surface morphology evolution of Si(100) during low-energy normal-incidence Ar + ion bombardmentIn situ analysis of Si(100) surface damage induced by low-energy rare-gas ion bombardment using x-ray photoelectron spectroscopy Effects of seed atoms on the formation of nanodots on silicon surfaces during normal incidence Ar + ion bombardment at room temperature are studied with real-time grazing-incidence small-angle x-ray scattering ͑GISAXS͒, real-time wafer curvature stress measurements and ex situ atomic force microscopy. Although Si surfaces remain smooth during bombardment at room temperature, when a small amount of Mo atoms is supplied to the surface during ion bombardment, the development of correlated structures ͑"dots"͒ is observed. Stress measurements show that initially a compressive stress develops during bombardment, likely due to amorphization of the surface and insertion of argon. However, seeding causes a larger tensile stress to develop with further bombardment, possibly due to the formation of higher density regions around the Mo seed atoms on the surface. Detailed fits of the GISAXS evolution during nanostructure growth show that the instability is larger than predicted by the Bradley-Harper theory of curvature-dependent sputter yield. These results suggest that the tensile stress is playing a dominant role in driving the nanodot formation.

Mass Redistribution Causes the Structural Richness of Ion-Irradiated Surfaces

“…A photon wavelength of 0.124 nm is selected by a Si(111) monochromator passing about 10 12 photons=s. In the GISAXS geometry, we take the z direction to be along the sample normal, the y direction to be along the projected direction of the x-ray beam onto the sample surface, and the x direction, the coordinate along which the linear position sensitive detector is oriented, to be along the sample surface and parallel to the projection of the ion beam [15]. The argon ions were generated using a PHI ion gun from Physical Electronics, Inc.…”

Multiple Bifurcation Types and the Linear Dynamics of Ion Sputtered Surfaces

“…To vary the incidence angle , samples were fixed, using melted indium, onto graphite wedges of various angles which were shielded everywhere from the ion beam by Si wafer shields. Thus, only silicon is exposed to the direct ion beam [8] and contaminationinduced dynamics [9] is suppressed. The ion flux from the source was 0:57 mA cm À2 in the plane perpendicular to the ion beam.…”

Sharp transition from ripple patterns to a flat surface for ion beam erosion of Si with simultaneous co-deposition of iron

“…Zhang, Brötzmann, and Hofsäss AIP Advances 2, 032123 (2012) 6. XPS spectrum of the Fe-Si surface layer.…”

“…[5][6][7][8][9][10][11][12][13][14] In particular, metallic surfactants like Fe and Mo induce pronounced dot and ripple patterns on Si substrates even during normal and near normal ion incidence sputter erosion. 2,8,9,[11][12][13] In the absence of co-deposition of foreign atoms and for normal and near normal ion incidence, even for incidence angles up to 50…”