Secondary Grain Growth in Thin Films

1985 ◽  
Vol 57 ◽  
Author(s):  
C. V. Thompson ◽  
Henry I. Smith

AbstractNormal grain growth in thin films leads to columnar grains with sizes roughly equal to the film thickness. In subsequent grain growth, a minor fraction of the grains continue to grow at appreciable rates, leading initially to a bimodal grain size distribution and ultimately to a monomodal distribution of grains with sizes much larger than the film thickness. Those grains which continue to grow, secondary grains, often have uniform or restricted texture, suggesting that in such cases surface energy minimization plays an important role in driving their preferential growth. Surface-energy-driven secondary grain growth can, in principle, lead to single crystal films. Turnbull and co-workers were among the first to apply rate theory to the analysis of grain boundary motion, grain growth, and recrystallization. These models have been adapted to describe surface-energy-driven secondary grain growth in thin films. Recent experiments on secondary grain growth in thin metallic and semiconductor films are reviewed. It has been shown that film thickness, film composition and surface topography have pronounced effects on growth rates, final grain sizes and orientations.

IUCrJ ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Nan Wang ◽  
Yu-Xiang Dai ◽  
Tian-Lin Wang ◽  
Hua-Zhe Yang ◽  
Yang Qi

The preferred orientation growth characteristics and surface roughness of polycrystalline bismuth (Bi) thin films fabricated on glass substrates using the molecular beam epitaxy method were investigated at temperatures ranging from 18 to 150°C. The crystallization and morphology were analyzed in detail and the polycrystalline metal film structure-zone model (SZM) was modified to fit the polycrystalline Bi thin film. The boundary temperature between Zone T and Zone II in the SZM shifted to higher temperatures with the increase in film thickness or the decrease of growth rate. Furthermore, the effect of the thickness and surface roughness on the transport properties was investigated, especially for Bi thin films in Zone II. A two-transport channels model was adopted to reveal the influence of the film thickness on the competition between the metallic surface states and the semiconducting bulk states, which is consistent with the results of Bi single-crystal films. Therefore, the polycrystalline Bi thin films are expected to replace the single-crystal films in the application of spintronic devices.


2012 ◽  
Vol 706-709 ◽  
pp. 2880-2885 ◽  
Author(s):  
Shigeaki Kobayashi ◽  
Ryouta Fukasawa ◽  
Tadao Watanabe

The evolution of grain boundary microstructures in gold thin films during annealing was investigated in order to find a clue to the development of high performance thin films by grain boundary engineering. The {111} oriented grains with the lowest surface energy were preferentially grown by surface energy-driven grain growth during annealing. The sharp {111} texture was developed by annealing at the temperature more than 873K. The remarkably high fraction of low-Σ coincidence site lattice (CSL) boundaries occurred when the area fraction of {111} texture increased to more than 95%. In particular, the fraction of some low-Σ CSL boundaries (Σ1,Σ3,Σ7) for the most sharply {111} textured specimen was found to be one order higher than those predicted for a random polycrystal. The utility of grain boundary engineering is discussed for controlling the performance degradation caused by the percolation phenomena of grain boundary diffusion in gold thin films.


2009 ◽  
Vol 1222 ◽  
Author(s):  
Man I Lei ◽  
Te-Hao Lee ◽  
Mehran Mehregany

AbstractThe effect of film thickness on the electrical resistivity of heavily-nitrogen-doped polycrystalline SiC (poly-SiC) thin films is investigated. The resistivity of poly-SiC thin films decreases by a factor of ˜7 for thickness increasing from 100 nm-thick to 1.78 μm-thick; the resistivity begins to stabilize as thickness approaches 1 μm. The increased resistivity for the thinner films is shown to be related to the grain boundary effect. Secondary ion mass spectrometry indicates a nitrogen concentration of 9×1020 atoms/cm3 in the films. However, Hall measurements reveal that only 45% of the dopants are electrically active in the 100 nm-thick film. The percentage of active dopants rises to 80% when film thickness increases to 680 nm. From the studies of surface roughness and microstructure, it is seen that small grains are formed at the initial stage of deposition, which then grow into larger columnar grains as film thickness increases. The presence of a large density of grain boundaries and limited grain growth for the very thin films contribute to increased electrical resistivity from increased trapped mobile carriers and reduced carrier mobility. The free carrier trapping phenomenon can further be observed in the temperature-dependence of resistance measurement.


2000 ◽  
Vol 15 (5) ◽  
pp. 1062-1068 ◽  
Author(s):  
W. Brückner ◽  
V. Weihnacht ◽  
W. Pitschke ◽  
J. Thomas ◽  
S. Baunack

The evolution in both stress and microstructure was investigated on sputtered Cu0.57Ni0.42Mn0.01thin films of 400 nm thickness during the first temperature cycle up to 550 °C. Samples from stress–temperature measurements up to various maximum temperatures were analyzed by x-ray diffraction, scanning and transmission electron microscopy, and Auger electron spectroscopy. The columnar grains with lateral diameters of about 20 nm in the as-deposited state coarsen to about 400 nm above 300 °C. Probably due to the impurity (Mn) drag effect, the coarsening occurs by abnormal grain growth rather than by normal grain growth, starting near the film–substrate interface. The stress development results from a combination of densification due to grain growth and plastic stress relaxation.


1994 ◽  
Vol 343 ◽  
Author(s):  
S. J. Townsend ◽  
C. S. Nichols

ABSTRACTDuring grain growth, shrinking columnar grains in thin-film polycrystalline microstructures eventually reach sizes comparable to the film thickness. Due to surface drag, the sides of such grains may bow inward rather than remaining fiat through the bulk of the film. The grain boundaries delimiting such small shrinking grains may become unstable long before the surface of the shrinking grain reaches zero area. We report simulation results demonstrating such an instability in the limit of infinite surface drag. This may lead to extremely rapid disappearance of 4- or 5- sided grains, such as have been recently observed in in situ hot-stage TEM experiments on aluminum thin film polycrystals.


1983 ◽  
Vol 25 ◽  
Author(s):  
T. Yonehara ◽  
C.V. Tihompson ◽  
Henry I. Smith

ABSTRACTThe growth of large secondary grains with (112) texture, and solid-state agglomeration to single-crystal islands have been observed by annealing ultra-thin (less than 1000Å) films of Ge. A driving force proportional to surface-energy anisotropy and inversely proportional to film thickness is believed to be responsible for both phenomena. The temperature for agglomeration decreases with film thickness, and is further depressed by the presence of Sn vapor. Patterning Ge into stripes increases secondary grain size and population. Encapsulation with a film of SiO2 suppresses agglomeration and alters crystallographic texture. A surface-relief structure of 0.2μm period and 300Å depth induces a (100) texture in some cases, and alters the morphology of agglomerated islands.


1983 ◽  
Vol 25 ◽  
Author(s):  
C.R.M. Grovenor ◽  
D.A. Smith

ABSTRACTRapid grain growth has been induced in semiconductor films at relatively low temperatures by allowing contact with metals or metal/semiconductor eutectic melts. Mechanisms by which such enhanced grain growth can occur are discussed, and Diffusion Induced Boundary Migration has been shown to be a plausible explanation for the experimental observations from the Sn/Ge, Al/Ge and Au/Ge systems. Interface migration driven by the decrease in free energy during phase transformations however provides a better explanation of the large Si grains produced on heating the Au/Si samples.


2016 ◽  
Vol 23 (03) ◽  
pp. 1650009 ◽  
Author(s):  
İ. A. KARIPER

This study examines the critical surface energy of manganese sulfite (MnSO[Formula: see text] crystalline thin film, produced via chemical bath deposition (CBD) on substrates. In addition, parachor, which is an important parameter of chemical physics, and its relationship with grain size, film thickness, etc., has been investigated for thin films. For this purpose, MnSO3 thin films were deposited at room temperature using different deposition times. Structural properties of the films, such as film thickness and average grain size, were examined using X-ray diffraction; film thickness and surface properties were measured by and atomic force microscope; and critical surface tension of MnSO3 thin films was measured with Optical Tensiometer and calculated using Zisman method. The results showed that critical surface tension and parachor of the films have varied with average grain size and film thickness. Critical surface tension was calculated as 32.97, 24.55, 21.03 and 12.76[Formula: see text]mN/m for 14.66, 30.84, 37.07 and 44.56[Formula: see text]nm grain sizes, respectively. Film thickness and average grain size have been increased with the deposition time and they were found to be negatively correlated with surface tension and parachor. The relationship between film thickness and parachor was found as [Formula: see text] whereas the relationship between average grain size and parachor was found as [Formula: see text] We also showed the relationships between parachor and some thin films parameters.


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