Influence of liner-system and Cu-layer thickness on the grain structure of electroplated Cu

Author(s):  
M. Mueller ◽  
J. Kriz ◽  
D. Meinhold ◽  
T. Zerna
2002 ◽  
Vol 746 ◽  
Author(s):  
D. Y. Oh ◽  
J. K. Park

ABSTRACTThe CoPt-20at.%C thin films of 20nm thickness were sputter-deposited in the form of CoPt/Cn (n=1: carbon layer thickness=4nm; n=4: each carbon layer thickness=1nm) and were transformation-annealed at 650°C for various times. Carbon was found to dissolve into CoPt lattice and enlarge the c/a ratio of the ordered CoPt lattice. The amount of carbon dissolution increases with the decreasing carbon layer thickness at a given total carbon concentration.The carbon dissolution larger than a critical amount can lead to a shift of the phase equilibrium of ordering and produce a stable fine two-phase mixture of ordered and disordered phases at the equi-atomic composition of Co:Pt. This results in a fine and uniform stagnant grain structure of about 20nm on annealing at 650°C. The carbon dissolution by increasing the c/a ratio of the ordered CoPt lattice reduces both the saturation magnetization and the magnetocrystalline anisotropy constant of the film and leads to a reduction of coercivity of CoPt films.


Author(s):  
E. F. Lindsey ◽  
C. W. Price ◽  
E. L. Pierce ◽  
E. J. Hsieh

Columnar structures produced by DC magnetron sputtering can be altered by using RF biased sputtering or by exposing the film to nitrogen pulses during sputtering, and these techniques are being evaluated to refine the grain structure in sputtered beryllium films deposited on fused silica substrates. Beryllium is brittle, and fractures in sputtered beryllium films tend to be intergranular; therefore, a convenient technique to analyze grain structure in these films is to fracture the coated specimens and examine them in an SEM. However, fine structure in sputtered deposits is difficult to image in an SEM, and both the low density and the low secondary electron emission coefficient of beryllium seriously compound this problem. Secondary electron emission can be improved by coating beryllium with Au or Au-Pd, and coating also was required to overcome severe charging of the fused silica substrate even at low voltage. The coating structure can obliterate much of the fine structure in beryllium films, but reasonable results were obtained by using the high-resolution capability of an Hitachi S-800 SEM and either ion-beam coating with Au-Pd or carbon coating by thermal evaporation.


Author(s):  
Alain Claverie ◽  
Zuzanna Liliental-Weber

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.


Author(s):  
Z. Horita ◽  
D. J. Smith ◽  
M. Furukawa ◽  
M. Nemoto ◽  
R. Z. Valiev ◽  
...  

It is possible to produce metallic materials with submicrometer-grained (SMG) structures by imposing an intense plastic strain under quasi-hydrostatic pressure. Studies using conventional transmission electron microscopy (CTEM) showed that many grain boundaries in the SMG structures appeared diffuse in nature with poorly defined transition zones between individual grains. The implication of the CTEM observations is that the grain boundaries of the SMG structures are in a high energy state, having non-equilibrium character. It is anticipated that high-resolution electron microscopy (HREM) will serve to reveal a precise nature of the grain boundary structure in SMG materials. A recent study on nanocrystalline Ni and Ni3Al showed lattice distortion and dilatations in the vicinity of the grain boundaries. In this study, HREM observations are undertaken to examine the atomic structure of grain boundaries in an SMG Al-based Al-Mg alloy.An Al-3%Mg solid solution alloy was subjected to torsion straining to produce an equiaxed grain structure with an average grain size of ~0.09 μm.


Author(s):  
K. Ogura ◽  
H. Nishioka ◽  
N. Ikeo ◽  
T. Kanazawa ◽  
J. Teshima

Structural appraisal of thin film magnetic media is very important because their magnetic characters such as magnetic hysteresis and recording behaviors are drastically altered by the grain structure of the film. However, in general, the surface of thin film magnetic media of magnetic recording disk which is process completed is protected by several-nm thick sputtered carbon. Therefore, high-resolution observation of a cross-sectional plane of a disk is strongly required to see the fine structure of the thin film magnetic media. Additionally, observation of the top protection film is also very important in this field.Recently, several different process-completed magnetic disks were examined with a UHR-SEM, the JEOL JSM 890, which consisted of a field emission gun and a high-performance immerse lens. The disks were cut into approximately 10-mm squares, the bottom of these pieces were carved into more than half of the total thickness of the disks, and they were bent. There were many cracks on the bent disks. When these disks were observed with the UHR-SEM, it was very difficult to observe the fine structure of thin film magnetic media which appeared on the cracks, because of a very heavy contamination on the observing area.


Author(s):  
P. J. Lee ◽  
D. C. Larbalestier

Several features of the metallurgy of superconducting composites of Nb-Ti in a Cu matrix are of interest. The cold drawing strains are generally of order 8-10, producing a very fine grain structure of diameter 30-50 nm. Heat treatments of as little as 3 hours at 300 C (∼ 0.27 TM) produce a thin (1-3 nm) Ti-rich grain boundary film, the precipitate later growing out at triple points to 50-100 nm dia. Further plastic deformation of these larger a-Ti precipitates by strains of 3-4 produces an elongated ribbon morphology (of order 3 x 50 nm in transverse section) and it is the thickness and separation of these precipitates which are believed to control the superconducting properties. The present paper describes initial attempts to put our understanding of the metallurgy of these heavily cold-worked composites on a quantitative basis. The composite studied was fabricated in our own laboratory, using six intermediate heat treatments. This process enabled very high critical current density (Jc) values to be obtained. Samples were cut from the composite at many processing stages and a report of the structure of a number of these samples is made here.


Author(s):  
H. Kung ◽  
A.J. Griffin ◽  
Y.C. Lu ◽  
K.E. Sickafus ◽  
T.E. Mitchell ◽  
...  

Materials with compositionally modulated structures have gained much attention recently due to potential improvement in electrical, magnetic and mechanical properties. Specifically, Cu-Nb laminate systems have been extensively studied mainly due to the combination of high strength, and superior thermal and electrical conductivity that can be obtained and optimized for the different applications. The effect of layer thickness on the hardness, residual stress and electrical resistivity has been investigated. In general, increases in hardness and electrical resistivity have been observed with decreasing layer thickness. In addition, reduction in structural scale has caused the formation of a metastable structure which exhibits uniquely different properties. In this study, we report the formation of b.c.c. Cu in highly textured Cu/Nb nanolayers. A series of Cu/Nb nanolayered films, with alternating Cu and Nb layers, were prepared by dc magnetron sputtering onto Si {100} wafers. The nominal total thickness of each layered film was 1 μm. The layer thickness was varied between 1 nm and 500 nm with the volume fraction of the two phases kept constant at 50%. The deposition rates and film densities were determined through a combination of profilometry and ion beam analysis techniques. Cross-sectional transmission electron microscopy (XTEM) was used to examine the structure, phase and grain size distribution of the as-sputtered films. A JEOL 3000F high resolution TEM was used to characterize the microstructure.


Author(s):  
F. Ma ◽  
S. Vivekanand ◽  
K. Barmak ◽  
C. Michaelsen

Solid state reactions in sputter-deposited Nb/Al multilayer thin films have been studied by transmission and analytical electron microscopy (TEM/AEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The Nb/Al multilayer thin films for TEM studies were sputter-deposited on (1102)sapphire substrates. The periodicity of the films is in the range 10-500 nm. The overall composition of the films are 1/3, 2/1, and 3/1 Nb/Al, corresponding to the stoichiometric composition of the three intermetallic phases in this system.Figure 1 is a TEM micrograph of an as-deposited film with periodicity A = dA1 + dNb = 72 nm, where d's are layer thicknesses. The polycrystalline nature of the Al and Nb layers with their columnar grain structure is evident in the figure. Both Nb and Al layers exhibit crystallographic texture, with the electron diffraction pattern for this film showing stronger diffraction spots in the direction normal to the multilayer. The X-ray diffraction patterns of all films are dominated by the Al(l 11) and Nb(l 10) peaks and show a merging of these two peaks with decreasing periodicity.


Author(s):  
Brian Ralph ◽  
Barlow Claire ◽  
Nicola Ecob

This brief review seeks to summarize some of the main property changes which may be induced by altering the grain structure of materials. Where appropriate an interpretation is given of these changes in terms of current theories of grain boundary structure, and some examples from current studies are presented at the end of this paper.


Author(s):  
Masahiro Ito ◽  
Yuitch Iwagaki ◽  
Hiroshi Murakami ◽  
Kenji Nemoto ◽  
Masato Yamamoto ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document