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Title: Morphology evolution on diamond surfaces during ion sputtering

Abstract

We have conducted an extensive study of the evolution of surface morphology of single crystal diamond surfaces during sputtering by 20 keV Ga{sup +} and Ga{sup +}+H{sub 2}O. We observe the formation of well-ordered ripples on the surface for angles of incidence between 40 and 70 deg.. We have also measured sputter yields as a function of angle of incidence, and ripple wavelength and amplitude dependence on angle of incidence and ion fluence. Smooth surface morphology is observed for <40 deg., and a transition to a step-and-terrace structure is observed for >70 deg.. The formation and evolution of well-ordered surface ripples is well characterized by the model of Bradley and Harper, where sputter-induced roughening is balanced by surface transport smoothing. Smoothing is consistent with an ion-induced viscous relaxation mechanism. Ripple amplitude saturates at high ion fluence, confirming the effect of nonlinear processes. Differences between Ga{sup +} and Ga{sup +}+H{sub 2}O in ripple wavelength, amplitude, and time to saturation of amplitude are consistent with the increased sputter yield observed for Ga{sup +}+H{sub 2}O. For angle of incidence <40 deg., an ion bombardment-induced 'atomic drift' mechanism for surface smoothing may be responsible for suppression of ripple formation. For Ga{sup +}+H{sub 2}O, wemore » observe anomalous formation of very large amplitude and wavelength, poorly ordered surface ridges for angle of incidence near 40 deg.. Finally, we observe that ripple initiation on smooth surfaces can take place by initial stochastic roughening followed by evolution of increasingly well-ordered ripples.« less

Authors:
; ; ;  [1]
  1. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
Publication Date:
OSTI Identifier:
20723205
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 23; Journal Issue: 6; Other Information: DOI: 10.1116/1.2110386; (c) 2005 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DIAMONDS; GALLIUM IONS; INCIDENCE ANGLE; ION BEAMS; KEV RANGE 10-100; MONOCRYSTALS; MORPHOLOGY; RELAXATION; ROUGHNESS; SPUTTERING; WAVELENGTHS

Citation Formats

Mayer, T.M., Adams, D.P., Vasile, M.J., and Archuleta, K.M. Morphology evolution on diamond surfaces during ion sputtering. United States: N. p., 2005. Web. doi:10.1116/1.2110386.
Mayer, T.M., Adams, D.P., Vasile, M.J., & Archuleta, K.M. Morphology evolution on diamond surfaces during ion sputtering. United States. doi:10.1116/1.2110386.
Mayer, T.M., Adams, D.P., Vasile, M.J., and Archuleta, K.M. Tue . "Morphology evolution on diamond surfaces during ion sputtering". United States. doi:10.1116/1.2110386.
@article{osti_20723205,
title = {Morphology evolution on diamond surfaces during ion sputtering},
author = {Mayer, T.M. and Adams, D.P. and Vasile, M.J. and Archuleta, K.M.},
abstractNote = {We have conducted an extensive study of the evolution of surface morphology of single crystal diamond surfaces during sputtering by 20 keV Ga{sup +} and Ga{sup +}+H{sub 2}O. We observe the formation of well-ordered ripples on the surface for angles of incidence between 40 and 70 deg.. We have also measured sputter yields as a function of angle of incidence, and ripple wavelength and amplitude dependence on angle of incidence and ion fluence. Smooth surface morphology is observed for <40 deg., and a transition to a step-and-terrace structure is observed for >70 deg.. The formation and evolution of well-ordered surface ripples is well characterized by the model of Bradley and Harper, where sputter-induced roughening is balanced by surface transport smoothing. Smoothing is consistent with an ion-induced viscous relaxation mechanism. Ripple amplitude saturates at high ion fluence, confirming the effect of nonlinear processes. Differences between Ga{sup +} and Ga{sup +}+H{sub 2}O in ripple wavelength, amplitude, and time to saturation of amplitude are consistent with the increased sputter yield observed for Ga{sup +}+H{sub 2}O. For angle of incidence <40 deg., an ion bombardment-induced 'atomic drift' mechanism for surface smoothing may be responsible for suppression of ripple formation. For Ga{sup +}+H{sub 2}O, we observe anomalous formation of very large amplitude and wavelength, poorly ordered surface ridges for angle of incidence near 40 deg.. Finally, we observe that ripple initiation on smooth surfaces can take place by initial stochastic roughening followed by evolution of increasingly well-ordered ripples.},
doi = {10.1116/1.2110386},
journal = {Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films},
number = 6,
volume = 23,
place = {United States},
year = {Tue Nov 15 00:00:00 EST 2005},
month = {Tue Nov 15 00:00:00 EST 2005}
}
  • We have conducted an extensive study of the evolution of surface morphology of single crystal diamond surfaces during sputtering by 20 keV Ga{sup +} and Ga{sup +} + H{sub 2}O. We observe the formation of well-ordered ripples on the surface for angles of incidence between 40 and 70{sup o}. We have also measured sputter yields as a function of angle of incidence, and ripple wavelength and amplitude dependence on angle of incidence and ion fluence. Smooth surface morphology is observed for <40{sup o}, and a transition to a step-and-terrace structure is observed for >70{sup o}. The formation and evolution ofmore » well-ordered surface ripples is well characterized by the model of Bradley and Harper, where sputter-induced roughening is balanced by surface transport smoothing. Smoothing is consistent with an ion-induced viscous relaxation mechanism. Ripple amplitude saturates at high ion fluence, confirming the effect of nonlinear processes. Differences between Ga{sup +} and Ga{sup +} + H{sub 2}O in ripple wavelength, amplitude, and time to saturation of amplitude are consistent with the increased sputter yield observed for Ga{sup +} + H{sub 2}O. For angle of incidence <40{sup o}, an ion bombardment-induced 'atomic drift' mechanism for surface smoothing may be responsible for suppression of ripple formation. For Ga{sup +} + H{sub 2}O, we observe anomalous formation of very large amplitude and wavelength, poorly ordered surface ridges for angle of incidence near 40{sup o}. Finally, we observe that ripple initiation on smooth surfaces can take place by initial stochastic roughening followed by evolution of increasingly well-ordered ripples.« less
  • The surface morphology of Si(100) induced by 1200 eV Ar{sup +} ion bombardment at normal incidence with and without Fe incorporation is presented. The formation of nanodot patterns is observed only when the stationary Fe areal density in the surface is above a threshold value of 8x10{sup 14} cm{sup -2}. This result is interpreted in terms of an additional surface instability due to locally nonuniform sputtering in connection with the presence of a Fe rich amorphous phase at the peak of the nanodots. At Fe concentrations below the threshold, smoothing dominates and pattern formation is inhibited. The transition from amore » k{sup -2} to a k{sup -4} behavior in the asymptotic power spectral density function supports the conclusion that under these conditions ballistic smoothing and ion-enhanced viscous flow are the two dominant mechanisms of surface relaxation.« less
  • Low-energy Ar{sup +}-ion bombardment of atomically rough (001) Si surfaces has been investigated using atomistic simulations. The simulations suggest that ions with energy less than 20 eV selectively displace surface atoms without causing bulk damage and further that the displacement yield is surface site specific in this energy range. Interpreted in the context of recent experimental kinetic data for Si-surface self-diffusion, the simulations imply that above room temperature the most important effect of ion bombardment on surface self-diffusion and surface morphology is an increase in the formation rate of single adatoms rather than enhancement of the migration component of surfacemore » self-diffusion.« less
  • We have investigated the temperature-dependent roughening kinetics of Ge surfaces during low energy ion sputtering using energy dispersive x-ray reflectivity. At 150 [degree]C and below, the surface is amorphized by ion impact and roughens to a steady state small value. At 250 [degree]C the surface remains crystalline, roughens exponentially with time, and develops a pronounced ripple topography. At higher temperature this exponential roughening is slower, with an initial sublinear time dependence. A model that contains a balance between smoothing by surface diffusion and viscous flow and roughening by atom removal explains the kinetics. Ripple formation is a result of amore » curvature-dependent sputter yield.« less
  • When collimated beams of low energy ions are used to bombard materials, the surface often develops a periodic pattern or 'ripple' structure. Different types of patterns are observed to develop under different conditions, with characteristic features that depend on the substrate material, the ion beam parameters, and the processing conditions. Because the patterns develop spontaneously, without applying any external mask or template, their formation is the expression of a dynamic balance among fundamental surface kinetic processes, e.g., erosion of material from the surface, ion-induced defect creation, and defect-mediated evolution of the surface morphology. In recent years, a comprehensive picture ofmore » the different kinetic mechanisms that control the different types of patterns that form has begun to emerge. In this article, we provide a review of different mechanisms that have been proposed and how they fit together in terms of the kinetic regimes in which they dominate. These are grouped into regions of behavior dominated by the directionality of the ion beam, the crystallinity of the surface, the barriers to surface roughening, and nonlinear effects. In sections devoted to each type of behavior, we relate experimental observations of patterning in these regimes to predictions of continuum models and to computer simulations. A comparison between theory and experiment is used to highlight strengths and weaknesses in our understanding. We also discuss the patterning behavior that falls outside the scope of the current understanding and opportunities for advancement.« less