Cross-sectional tem analysis of solvent-cast SBS thin films

Author(s):  
G. Kim ◽  
M. Libera

Block copolymers can assume a range of microphase-separated morphologies, and the dependence of morphology on temperature and composition is an area of active research. Our work has been studying the morphology of solvent-cast thin films of polystyrene-polybutadiene-polystyrene (SBS) as a function of solvent evaporation rate and post-specimen annealing. This paper describes the analysis of thin film cross-sections to distinguish between possible morphologies. ∼50 nm-0.5 μm thick films were cast from a 0.1 wt% solution of SBS (30 wt%, Mw=105) in toluene. GPC analysis indicates PS/PB diblock and PS homopolymer is present (<5wt% total). 50 μl of solution was deposited on water-polished salt. The solvent evaporation rate was roughly controlled between 200 nl/sec and 0.2 nl/sec. After evaporation, the film was cut, floated from the salt, collected on grids, and exposed to OsO4 vapor (20 min) to stain the PB. After plan view study, some specimens were cross-sectioned. A carbon layer was evaporated on both sides prior to embedding in epoxy and ultramicrotomy(−130°C). Microscopy used a Philips CM3 0ST TEM.

2010 ◽  
Vol 16 (6) ◽  
pp. 662-669 ◽  
Author(s):  
S. Simões ◽  
F. Viana ◽  
A.S. Ramos ◽  
M.T. Vieira ◽  
M.F. Vieira

AbstractReactive multilayer thin films that undergo highly exothermic reactions are attractive choices for applications in ignition, propulsion, and joining systems. Ni/Al reactive multilayer thin films were deposited by dc magnetron sputtering with a period of 14 nm. The microstructure of the as-deposited and heat-treated Ni/Al multilayers was studied by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) in plan view and in cross section. The cross-section samples for TEM and STEM were prepared by focused ion beam lift-out technique. TEM analysis indicates that the as-deposited samples were composed of Ni and Al. High-resolution TEM images reveal the presence of NiAl in small localized regions. Microstructural characterization shows that heat treating at 450 and 700°C transforms the Ni/Al multilayered structure into equiaxed NiAl fine grains.


2008 ◽  
Vol 3 ◽  
pp. 59-66 ◽  
Author(s):  
Jiechao Jiang ◽  
J. He ◽  
Efstathios I. Meletis ◽  
Jian Liu ◽  
Z. Yuan ◽  
...  

Two-dimensional in-plane interface structures of highly epitaxial perovskite (La,Ca)MnO3 (LCMO) and (Pb,Sr)TiO3 (PSTO) thin films on salt-rock type MgO substrate were studied using Transmission Electron Microscopy (TEM). Cross-section TEM studies revealed that both LCMO and PSTO films are good single crystal quality and have atomic sharp interface with respect to the MgO substrate with -6.4% and -6.2% lattice mismatch, respectively. Electron Diffraction Patterns (EDPs) of plan-view LCMO/MgO and PSTO/MgO interfaces exhibit double diffraction spots. An analytical approach was employed using double diffraction to study the two-dimensional in-plane interfaces of perovskite structure films on the salt-rock type substrate. The lattice mismatch near the interface regions was determined using EDPs of the plan-view interfaces and found to be -8.0% for LCMO/MgO and -7.14% for PSTO. Both latter values are larger than those obtained using cross-section TEM. Studies of the sharpness of double diffraction spots and plan-view high resolution (HR) TEM brought a conclusion that the PSTO film is well commensurate with the MgO substrate over large areas, whereas LCMO film is only locally commensurate with the substrate. These studies provide additional evidence to our previous observations that plan-view TEM of the interface is able to provide critical and valuable information that is lacking from the cross-section TEM analysis.


1999 ◽  
Vol 5 (S2) ◽  
pp. 908-909
Author(s):  
J.L. Drown-MacDonald ◽  
B.I. Prenitzer ◽  
T.L. Shofner ◽  
L.A. Giannuzzi

Focused Ion Beam (FIB) specimen preparation for both scanning and transmission electron microscopy (SEM and TEM respectively) has seen an increase in usage over the past few years. The advantage to the FIB is that site specific cross sections (or plan view sections) may be fabricated quickly and reproducibly from numerous types of materials using a finely focused beam of Ga+ ions [1,2]. It was demonstrated by Prenitzer et al. that TEM specimens may be acquired from individual Zn powder particles by employing the FIB LO specimen preparation technique [3]. In this paper, we use the FIB LO technique to prepare TEM specimens from Mount Saint Helens volcanic ash.Volcanic ash from Mount Saint Helens was obtained at the Microscopy and Microanalysis 1998 meeting in Atlanta. TEM analysis of the ash was performed using the FIB lift out technique [1]. Ash powders were dusted onto an SEM sample stud that had been coated with silver paint.


1996 ◽  
Vol 11 (12) ◽  
pp. 2951-2954 ◽  
Author(s):  
J. G. Wen ◽  
S. Mahajan ◽  
H. Ohtsuka ◽  
T. Morishita ◽  
N. Koshizuka

Highly in-plane aligned α-axis YBa2Cu3O7−x thin films deposited on (100) LaSrGaO4 substrates by a self-template method were studied by high-resolution electron microscopy along three orthogonal 〈100〉 axes of the substrate. Plan-view images confirm that the majority of the film preferentially aligns across the entire substrate except for very few misaligned domains with average size 10 nm2. Cross-sectional images along the [100] orientation of YBa2Cu3O7−x reveal that in-plane aligned α-axis YBa2Cu3O7−x is grown on a template layer dominated by c-axis oriented film. This strongly suggests that the in-plane alignment of α-axis YBa2Cu3O7−x thin films on (100) LaSrGaO4 substrates is governed by the different stresses along the b and c axes of the substrate. Cross-sectional images along [001] of the YBa2Cu3O7—x thin film reveal that the 90° domains easily nucleate in the region between α-axis YBa2Cu3O7—x and the YBa4Cu3Ox phase. Cracks along the (001) plane of YBa2Cu3O7−x are found to be due to the large mismatch between the c parameters of the thin film and substrate.


2007 ◽  
Vol 1049 ◽  
Author(s):  
Nursiani Indah Tjahyono ◽  
Yu Lung Chiu

AbstractThe microstructure and mechanical properties of nanocrystalline copper with grain size ranging from 50 nm to 80 nm have been investigated. Thin films of nanocrystalline copper were electrodeposited from an additive-free acidified copper sulphate solution at room temperature by employing constant current at different current density magnitudes between 20 and 80 mA/cm2. Both austenitic and ferritic steel substrates with the same surface finishing conditions have been used for the deposition. The microstructure of the thin films has been further studied using electron microscopy techniques, and the mechanical properties using nanoindentation technique. The nanoindentation study was carried out on both the plan view and cross-sectional directions to study the isotropy characteristic of the copper film. It has been noted that both the modulus and hardness measured following the Oliver-Pharr scheme show an apparent indentation size effect tested on the cross-sectional sample.


Author(s):  
R.M. Fisher ◽  
J.Z. Duan ◽  
Crispin J. Hetherington ◽  
Norman Fowler

The resistance of deposited thin films to cracking or delamination from substrates during production or service, crucial to the long term reliability of IC devices, is under study as part of a broad program on interfacial bonding and adhesion. Chromium films, of particular interest because of their widespread use in microelectronics, are especially prone to mechanical failure due to the high residual stresses that are generally present and their low fracture toughness. Transmission and scanning electron microscopy are being used to define the columnar grain structure and failure modes and x-ray diffraction is being employed to determine the nature of through-thickness stress gradients that occur in such films.The intrinsic stress, as distinguished from the extrinsic stress caused by differential contraction between film and substrate during cooling from the deposition temperature, results from the presence of vacancies and diffuse “voids” trapped between the columns during deposition. Transmission electron microscopy of plan-view and cross-sections is being used in efforts to observe and define the structure of the inter-columnar regions.


1999 ◽  
Vol 5 (S2) ◽  
pp. 516-517
Author(s):  
Lucille A. Giannuzzi

The focused ion beam (FIB) instrument has been developed and exploited by the microelectronics arena for specimen preparation for both scanning and transmission electron microscopy (TEM). The inception [1] and subsequent development [2] of the FIB TEM lift-out (LO) technique has enabled electron transparent membranes of generally uniform thickness to be produced for TEM analysis. The primary advantage of the FIB technique is that site specific cross sections (or plan view sections [3]) may be fabricated quickly and reproducibly. The FIB LO technique has been used extensively in our laboratory for a wide range of materials [4] and biological applications [5] which are summarized in figure 1.The FIB LO method consists of milling a series of trenches around an area of interest. Then the bulk sample is tilted up to ∼60 degrees to allow the beam to impinge on the lower portion of the specimen surface so that cuts can be made along the bottom edge and the lower 2/3 of the distance up one side of the specimen.


1990 ◽  
Vol 199 ◽  
Author(s):  
Shang. H. Rou ◽  
Philip. D. Hren ◽  
Angus. I. Kingon

ABSTRACTSingle crystal MgO is a common substrate for the deposition of oxide thin films. The conventional cross sectional transmission electron microscopy sample preparation procedure suffers the drawbacks of: 1)- extensive ion milling time; 2) a higher milling rate for the thin films than for the substrate; 3) introduction of artifacts and contamination during ion milling; and 4) generation of excess defects into the substrate during mechanical thinning. An additional chemical thinning step using hot orthophosphoric acid can reduce or eliminate these adverse effects.This technique can be applied generally to thin film samples deposited on substrates with a low ion milling rate. Furthermore, substrates which are sensitive to mechanical stress and ion beam damage are also suitable for this technique, provided an appropriate chemical polishing solution and compatible epoxy can be found. The unique features of this technique are briefly presented.


Sign in / Sign up

Export Citation Format

Share Document