Pressure-dependent transition from atoms to nanoparticles in magnetron sputtering: Effect on<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>WSi</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>film roughness and stress

Zhou, Lan; Wang, Yiping; Zhou, Hua; Li, Minghao; Headrick, Randall L.; MacArthur, Kimberly; Shi, Bing; Conley, Ray; Macrander, Albert T.

doi:10.1103/physrevb.82.075408

Cited by 15 publications

(16 citation statements)

References 52 publications

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“…This pressure range is chosen because it is above the roughening transition pressure for WSi 2 (∼6 mtorr; ref. 35). The sample stage was replaced with a quartz crystal microbalance for calibration of deposition rates.…”

Section: Methodsmentioning

confidence: 93%

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Direct measurement of the propagation velocity of defects using coherent X-rays

et al. 2016

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The properties of artificially grown thin films are often strongly a ected by the dynamic relationships between surface growth processes and subsurface structure. Coherent mixing of X-ray signals promises to provide an approach to better understand such processes. Here, we demonstrate the continuously variable mixing of surface and bulk scattering signals during realtime studies of sputter deposition of a-Si and a-WSi2 films by controlling the X-ray penetration and escape depths in coherent grazing-incidence small-angle X-ray scattering. Under conditions where the X-ray signal comes from both the growth surface and the thin film bulk, oscillations in temporal correlations arise from coherent interference between scattering from stationary bulk features and from the advancing surface. We also observe evidence that elongated bulk features propagate upwards at the same velocity as the surface. Furthermore, a highly surface-sensitive mode is demonstrated that can access the surface dynamics independently of the subsurface structure.A key objective for understanding surface dynamics during thin film growth is the ability to monitor nanometre-scale surface fluctuation dynamics in real time 1-3 . These fluctuations of roughness and density occur on timescales that rarely exceed a few seconds, and take place in environments that are inaccessible to most high spatial resolution probes. For example, scanning probe microscopy is widely used to study interfacial reactivity in non-vacuum environments 4 , but is limited by its inability to probe surfaces in real time during deposition; electron microscopy is mainly limited to high-vacuum environments and low magnetic fields 5,6 . X-rays have the potential to overcome these challenges owing to their highly penetrating nature and sensitivity to nanometrescale features. Observation of subsurface structures in real time during film growth appears to be even more challenging, and has rarely been attempted 7 . Bulk signals are sometimes observed as unwanted background in grazing-incidence surface X-ray scattering experiments, but there have been few attempts to quantitatively understand the features responsible for such signals 8,9 .The interaction of surfaces with nanometre-scale buried defects and the formation of bulk defects at a growing surface are integral to many industrial processes. For example, misfit dislocations nucleate at free surfaces and buried interfaces in strained-layer epitaxial growth of layers for photonic devices 10 ; motion and ordering of oxygen vacancies in complex oxide materials for ferroelectric memory depend on the surface conditions during growth 11-13 ; and voids in electrochemically deposited layers used for interconnects in electronic circuits are introduced by surface processes during deposition 14 .The use of X-ray scattering techniques to probe in situ realtime processes has largely been restricted to well-ordered crystalline structures and to statistical averages of disorder, owing to limitations in the spectral brightness of X-ray sources. A fu...

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Section: Methodsmentioning

confidence: 93%

“…We find that amorphous surfaces often obey the Family-Vicsek scaling relation for surface growth [33][34][35] :…”

Section: Figure 2 | Static Intensities During Steady-state Growthmentioning

confidence: 98%

Direct measurement of the propagation velocity of defects using coherent X-rays

et al. 2016

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“…8). The pressure between 6 mTorr and 8 mTorr most presumably corresponds to a critical transition pressure, called "thermalization pressure" (P c ) [38], under which the particles travel ballistically through the plasma and attain the growing surface with high velocity. Increasing the pressure also increases the number of collisions in the plasma, decreasing the kinetic energy of the species.…”

Section: Effect Of Deposition Pressure On Internal Stress Porosity and Roughnessmentioning

confidence: 99%

“…Above P c , particles attain the substrate with an energy reduced to the thermal energy. Zhou et al [38] combined the thermalization effect to a model of aggregate formation to explain the abrupt roughness transition observed above P c . In their model, above P c , the size of the clusters increases with pressure.…”

Section: Effect Of Deposition Pressure On Internal Stress Porosity and Roughnessmentioning

confidence: 99%

Mechanical behavior of ultrathin sputter deposited porous amorphous Al2O3 films

et al. 2017

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The determination of the mechanical properties of porous amorphous Al 2 O 3 thin films is essential to address reliability issues in wear-resistant, optical and electronic coating applications. Testing the mechanical properties of Al 2 O 3 films thinner than 200 nm is challenging, and the link between the mechanical behavior and the microstructure of such films is largely unknown. Herein, we report on the elastic and viscoplastic mechanical properties of amorphous Al 2 O 3 thin films synthesized by reactive magnetron sputtering using a combination of internal stress, nanoindentation, and on-chip uniaxial tensile testing characterization, together with mechanical homogenization models to separate the effect of porosity from intrinsic variations of the response of the sound material. The porosity is made of voids with 2 to 30 nm diameter. The Young's modulus and hardness of the films decrease by a factor of two when the deposition pressure increases from 1.2 to 8 mTorr. The contribution of porosity was found to be small, and a change in the atomic structure of the amorphous Al 2 O 3 matrix is hypothesized to be the main contributing factor. The activation volume associated to the viscoplastic mechanism is around 100 . Differences in the atomic structure of the films could not be revealed by electron diffraction, pointing to a minute effect of atomic arrangement on the elastic properties.

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“…Metallic aggregates have attracted much attention in recent years because of their fundamental importance and potential applications in microelectronic devices, biosensors, catalysts, and other devices. [1][2][3][4][5][6][7] Recently, considerable theoretical 8,9) and experimental 10,11) efforts have been made to understand the fundamental aggregation of atomic aggregates, which is related to the fabrication conditions, such as deposition flux, substrate temperature, and substrate properties. As a consequence, it is very important and highly feasible to control the evolution of surface morphology during the growth of the aggregates.…”

Section: Introductionmentioning

confidence: 99%

Aggregation Mechanism of Ag Atoms Deposited on Liquid Surfaces

Zhang

Yang

et al. 2011

J. Phys. Soc. Jpn.

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We study the aggregation of silver (Ag) atoms deposited on silicone oil surfaces. It is observed that the apparent Ag coverage of the total area, &, increases linearly with the nominal film thickness h for h < 0:9 nm and its slope k decreases clearly as the deposition flux f increases. Our atomic force microscopy (AFM) observation shows that the average thickness of the atomic aggregates first increases with f , and then approaches a saturation value. Then, the aggregation mechanism of Ag atoms is presented.

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Pressure-dependent transition from atoms to nanoparticles in magnetron sputtering: Effect onWSi2film roughness and stress

Cited by 15 publications

References 52 publications

Direct measurement of the propagation velocity of defects using coherent X-rays

Direct measurement of the propagation velocity of defects using coherent X-rays

Mechanical behavior of ultrathin sputter deposited porous amorphous Al2O3 films

Aggregation Mechanism of Ag Atoms Deposited on Liquid Surfaces

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