Growth of patterned island arrays to identify origins of thin film stress

Chason, E.; Shin, Jae Wook; Chen, C.-H.; Engwall, A. M.; Miller, Christopher; Hearne, Sean J.; Freund, L. B.

doi:10.1063/1.4870051

Cited by 19 publications

(10 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To provide a framework for understanding stress evolution, we have proposed a kinetic model (4,5) that predicts the stress evolution as a function of the growth conditions (temperature (T), diffusivity (D), and growth rate (R)) as well as the microstructure (grain size (L)). The model has been shown to be consistent with several studies of stress versus thickness for uniform and patterned (6,7) films and stress versus growth rate (5,8). However, the validity and limits of the model need to be explored by comparing its predictions with a wider range of experimental results.…”

Section: Introductionsupporting

confidence: 57%

Origins of residual stress in thin films: Interaction between microstructure and growth kinetics

2016

Self Cite

View full text Add to dashboard Cite

Thin films can develop large residual stresses during their growth that significantly impact their performance. Therefore, there is a need to understand how the stress is related to the developing film structure and underlying kinetic processes. In this work, we describe measurements of stress and the corresponding grain structure during electrodeposition of Ni and Cu films. For Ni deposition, the grain size stays nearly constant during growth and the stress reaches a nearly constant steady-state. For Cu deposition, the grain size grows as the thickness increases and the microstructural evolution affects the evolution of the stress. To remove the effect of subsurface grain growth on the stress, measurements were also done with periodic pauses that allowed the stress induced by grain growth to saturate. We interpret the results in terms of a kinetic model for stress evolution that focuses on the developing boundary between adjacent grains while the film is deposited. The effect of grain growth on stress for different types of microstructural evolution is also discussed. After accounting for the stress from subsurface grain growth, the results are consistent with the model for the dependence on growth rate and grain size at the surface.

show abstract

Section: Introductionsupporting

confidence: 57%

Origins of residual stress in thin films: Interaction between microstructure and growth kinetics

2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Figure 2 compares the MOSS in situ stress characterizations with the X-ray diffraction ex situ strain measurements of (001)-oriented SDC films on the different substrates. The MOSS measurements are reported as stress-thickness product (directly proportional to the curvature, from the Stoney equation (1) ) in function of thickness, a plot commonly used in the literature for wafer curvature measurements 19 20 21 22 23 24 25 .…”

Section: Resultsmentioning

confidence: 99%

“…Several examples of MOSS (or similar techniques) applications for studying the stress evolution during the growth of semiconductor or metal thin films exist 18 19 20 21 22 23 24 , whereas reports on MOSS diagnostic with oxide materials are very rare 25 . To our knowledge, this technique has never been applied simultaneously with RHEED during PLD, the most widespread method for the growth of oxide films.…”

mentioning

confidence: 99%

In situ stress observation in oxide films and how tensile stress influences oxygen ion conduction

et al. 2016

View full text Add to dashboard Cite

Many properties of materials can be changed by varying the interatomic distances in the crystal lattice by applying stress. Ideal model systems for investigations are heteroepitaxial thin films where lattice distortions can be induced by the crystallographic mismatch with the substrate. Here we describe an in situ simultaneous diagnostic of growth mode and stress during pulsed laser deposition of oxide thin films. The stress state and evolution up to the relaxation onset are monitored during the growth of oxygen ion conducting Ce0.85Sm0.15O2-δ thin films via optical wafer curvature measurements. Increasing tensile stress lowers the activation energy for charge transport and a thorough characterization of stress and morphology allows quantifying this effect using samples with the conductive properties of single crystals. The combined in situ application of optical deflectometry and electron diffraction provides an invaluable tool for strain engineering in Materials Science to fabricate novel devices with intriguing functionalities.

show abstract

“…However, validation of this model is difficult because the shape of individual islands (and hence the rate of grain boundary formation) is not known during the film growth. To overcome this problem, we have grown patterned arrays of islands in which the geometry during growth is known [16,17,18]. In the current work, we study stress evolution in a linear array in which the islands grow in the form of half-cylinders.…”

mentioning

confidence: 99%

Stress evolution during growth of 1-D island arrays: Kinetics and length scaling

et al. 2015

Self Cite

View full text Add to dashboard Cite

To explore the mechanisms controlling residual stress in thin films, we have measured the stress evolution during electrodeposition of Ni on lithographically patterned substrates with different pattern spacings and growth rates. Studying films with a controlled island geometry allows us to relate the stress (measured using wafer curvature) to the evolution of the morphology. We analyze the measurements with a model that focuses on the stress that develops where adjacent islands grow together to form new elements of grain boundary. Residual stress in polycrystalline thin films is a persistent problem, since it can significantly reduce film performance or lead to failure [1]. A deeper understanding would enable it to be predicted and controlled. Numerous studies have shown how the stress evolution depends on the material, processing conditions and evolving microstructure (many studies are reviewed in [2,3,4]). Films with low atomic mobility tend to grow in a state of tensile stress while films with higher mobility are compressive. Similarly, raising the growth temperature [5] or decreasing the growth rate [6] can change the stress from tensile to compressive. During growth, the stress goes through multiple states that correspond with the evolving microstructure, i.e., from isolated nuclei (low or compressive stress) through island coalescence (tensile stress) to a continuous film (steady-state stress that depends on growth rate) [7]. Various mechanisms have been proposed to explain different aspects of the stress evolution. Compressive stress in the nucleation stage has been attributed to lattice compression induced by the surface stress [8]. Hoffman [9] proposed that the tensile stress arises due to attractive forces between islands when the grain boundary forms, similar to the reason for cracks closing [10]. The origin of the post-coalescence compressive stress is more controversial, with various groups attributing it to: adatoms on

show abstract

Growth of patterned island arrays to identify origins of thin film stress

Cited by 19 publications

References 16 publications

Origins of residual stress in thin films: Interaction between microstructure and growth kinetics

Origins of residual stress in thin films: Interaction between microstructure and growth kinetics

In situ stress observation in oxide films and how tensile stress influences oxygen ion conduction

Stress evolution during growth of 1-D island arrays: Kinetics and length scaling

Contact Info

Product

Resources

About