Comparison of Cvd and Pvd Tungsten for Gigabit-Scale Dram Interconnections

1996 ◽  
Vol 427 ◽  
Author(s):  
John M. Drynan ◽  
Kuniaki Koyama
Keyword(s):  
Sheet Resistance ◽  
Crystal Orientation ◽  
Total Thickness ◽  
Preferential Growth ◽  
Materials Properties ◽  
Lower Resistance

AbstractThe characteristics of blanket CVD-W and PVD-W films with and without TiN/Ti underlayers have been investigated in terms of both materials properties such as resistance, stress, morphology, crystallinity, and composition, and prospective applications such as for DRAM bit line interconnections. The presence of a TiN underlayer has been found to induce preferential growth of dominant W (110) crystal orientation for both CVD-W and PVD-W whereas absence of TiN results in a W film of mixed W (110), (200), and (211) crystallites. Sheet resistance measurements of both blank films and conductor lines have shown that a 200nm-thick PVD-W film yields a lower resistance than a similar film with TiN underlayer and hence larger total thickness. This correspondence of W (110) intensity with resistance implies that reduction of the (110) oriented crystallites within a W film can yield lower resistances. Thus, by elimination of the TiN/Ti underlayer, monolayer PVD-W or CVD-W with a PVD-W underlayer can be effectively adapted to quarter-micron conductors for bit line interconnections and related structures in DRAM memory and other ULSI devices.

Effect of Nitrogen Diffusion in Ti and TiTiN Films for Future DRAM Bit Line Interconnects and Plugs

1996 ◽  
Vol 429 ◽  
Author(s):  
John M. Drynan ◽  
Kuniaki Koyama
Keyword(s):  
Solid Solution ◽  
Gas Phase ◽  
Sheet Resistance ◽  
Solid Phase ◽  
Deposition Process ◽  
Thermal Treatments ◽  
Nitrogen Diffusion ◽  
Materials Properties ◽  
Post Deposition

AbstractThe effects of nitrogen diffusion from both N2 gas phase and TiN solid phase sources on the characteristics of Ti/TiN bilayer and TiN/Ti/TiN trilayer films have been investigated in terms of both materials properties such as resistance, coloration, composition, and crystallinity, and prospective applications such as for DRAM bit line interconnections and contact-hole plugs. Using blank films it has been found, in coincidence with other work, that at the onset of N diffusion and hence low N concentrations within a Ti film, the sheet resistance increases and the Ti layer becomes a solid solution of N in hexagonal Ti. As the concentration increases, the sheet resistance reaches a maximum, after which it decreases abruptly and the structure becomes primarily tetragonal Ti2N phase. At higher concentrations the resistance stabilizes or increases slightly and the structure becomes more cubic TiN phase. Sheet resistances calculated from resistance measurements of Ti and TiN mono- and multilayer conductor lines with and without RTN and RTAr thermal treatments have shown that the conductor lines exhibit similar behavior to the blank films. In comparison with the mon-olayer lines, the multilayer ones are generally lower in resistance and more stable over a wider range of post-deposition process temperatures.

Microstructure of Pvd Al Deposition on CVD Tin

1997 ◽  
Vol 3 (S2) ◽  
pp. 493-494
Author(s):  
Na Zhang ◽  
Mark McNicholas ◽  
Bob Anderhalt ◽  
Evan Slow ◽  
Neil Colvin
Keyword(s):  
Sheet Resistance ◽  
Crystal Orientation ◽  
Tin Films ◽  
Tin Film ◽  
Secondary Role ◽  
Step Coverage ◽  
System 2

CVD TiN films offer promise as a barrier to Al deposition as a result of the improved conformai step coverage of this film in 0.25 μm contact holes. As an underlayer, the TiN performs a secondary role by improving electromigration (EM) resistance. This is a result of the crystal orientation of the TiN film and its influence on the orientation of the subsequent Al layer. A <111>Al orientation shows improved EM resistance; however, CVD TiN has a preferred <200> orientation as opposed to a <111>PVD TiN orientation.In this study, two parts were investigated: 1) obtain a qualified PVD Al film on a CVD <200> TiN barrier in terms of sheet resistance and reflectivity utilizing MRC's Eclipse™ Mark II PVD system; 2) examine the texture of the Al film utilizing Philips XL30 SEM equipped with EDAX-DX4 EDS system and Electron Back Scatter Pattern (EBSP) system.

Crystal orientation and growth anisotropy of YBa2Cu3O6+x fabricated by directional solidification method

1994 ◽  
Vol 9 (6) ◽  
pp. 1350-1356 ◽  
Author(s):  
Y. Nakamura ◽  
K. Furuya ◽  
T. Izumi ◽  
Y. Shiohara
Keyword(s):  
Crystal Orientation ◽  
Three Dimensional ◽  
Growth Direction ◽  
Zone Melting ◽  
Unidirectional Solidification ◽  
Interface Morphology ◽  
Preferential Growth ◽  
Melting Method ◽  
Steady Growth ◽  
Growth Anisotropy

The unidirectional solidification by a zone-melting method was performed to investigate the growth anisotropy of YBa2Cu3O6+x (123) superconductive oxides. Large faceted interfaces were obtained at growth rates lower than 2 mm/h. The three-dimensional interface morphology and the onset of growth were observed. The crystal faces toward the growth direction were revealed to be close to the {112} face, which was selected as the result of the preferential growth. The growth rate of the {100} faces was evaluated to be about 1.5 times faster than that of the {001} faces from the steady growth condition.

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

The Interpretation of Crystal Lattice Images

1972 ◽  
Vol 30 ◽  
pp. 550-551
Author(s):  
J. M. Cowley ◽  
Sumio Iijima
Keyword(s):  
Crystal Orientation ◽  
Diffraction Theory ◽  
Phase Changes ◽  
Electron Wave ◽  
Crystal Lattices ◽  
Heavy Atoms ◽  
Lattice Images ◽  
The Right ◽  
Intuitive Interpretation ◽  
Suitable Approximation

The imaging of detailed structures of crystal lattices with 3 to 4Å resolution, given the correct conditions of microscope defocus and crystal orientation and thickness, has been used by Iijima (this conference) for the study of new types of crystal structures and the defects in known structures associated with fluctuations of stoichiometry. The image intensities may be computed using n-beam dynamical diffraction theory involving several hundred beams (Fejes, this conference). However it is still important to have a suitable approximation to provide an immediate rough estimate of contrast and an evaluation of the intuitive interpretation in terms of an amplitude object.For crystals 100 to 150Å thick containing moderately heavy atoms the phase changes of the electron wave vary by about 10 radians suggesting that the “optimum defocus” theory of amplitude contrast for thin phase objects due to Scherzer and others can not apply, although it does predict the right defocus for optimum imaging.

Applications of Transmission Electron Microscopy in the Characterization of Metal Machinability

1968 ◽  
Vol 26 ◽  
pp. 442-443 ◽  
Author(s):  
L.E. Murr ◽  
A.B. Draper
Keyword(s):  
Electron Microscopy ◽  
State Physics ◽  
Test Material ◽  
Milling Machine ◽  
Rotary Table ◽  
Solid State Physics ◽  
Materials Properties ◽  
Transmission Electron ◽  
Selection Of

The industrial characterization of the machinability of metals and alloys has always been a very arbitrarily defined property, subject to the selection of various reference or test materials; and the adoption of rather naive and misleading interpretations and standards. However, it seems reasonable to assume that with the present state of knowledge of materials properties, and the current theories of solid state physics, more basic guidelines for machinability characterization might be established on the basis of the residual machined microstructures. This approach was originally pursued by Draper; and our presentation here will simply reflect an exposition and extension of this research.The technique consists initially in the production of machined chips of a desired test material on a horizontal milling machine with the workpiece (specimen) mounted on a rotary table vice. A single cut of a specified depth is taken from the workpiece (0.25 in. wide) each at a new tool location.

Study of segregation in La1.8Sr0.2CuO4 superconductor by STEM-EDS microanalysis

1987 ◽  
Vol 45 ◽  
pp. 54-55
Author(s):  
T. F. Kelly ◽  
P. J. Lee ◽  
E. E. Hellstrom ◽  
D. C. Larbalestier
Keyword(s):  
Rare Earth ◽  
High Field ◽  
Transport Current ◽  
Total Thickness ◽  
New Class ◽  
Ceramic Superconductors ◽  
Current Densities ◽  
Group Ii ◽  
Eds Microanalysis

Recently there has been much excitement over a new class of high Tc (>30 K) ceramic superconductors of the form A1-xBxCuO4-x, where A is a rare earth and B is from Group II. Unfortunately these materials have only been able to support small transport current densities 1-10 A/cm2. It is very desirable to increase these values by 2 to 3 orders of magnitude for useful high field applications. The reason for these small transport currents is as yet unknown. Evidence has, however, been presented for superconducting clusters on a 50-100 nm scale and on a 1-3 μm scale. We therefore planned a detailed TEM and STEM microanalysis study in order to see whether any evidence for the clusters could be seen.A La1.8Sr0.2Cu04 pellet was cut into 1 mm thick slices from which 3 mm discs were cut. The discs were subsequently mechanically ground to 100 μm total thickness and dimpled to 20 μm thickness at the center.

Effect of a Ti-capped and Ti-mediated Layer on Co Silicide Formation

2002 ◽  
Vol 716 ◽  
Author(s):  
G.Z. Pan ◽  
E.W. Chang ◽  
Y. Rahmat-Samii
Keyword(s):  
Electron Diffraction ◽  
Sheet Resistance ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Diffusion Barrier ◽  
Silicide Formation ◽  
Plan View ◽  
Processing Window

AbstractWe comparatively studied the formation of ultra thin Co silicides, Co2Si, CoSi and CoSi2, with/without a Ti-capped and Ti-mediated layer by using rapid thermal annealing in a N2 ambient. Four-point-probe sheet resistance measurements and plan-view electron diffraction were used to characterize the silicides as well as the epitaxial characteristics of CoSi2 with Si. We found that the formation of the Co silicides and their existing duration are strongly influenced by the presence of a Ti-capped and Ti-mediated layer. A Ti-capped layer promotes significantly CoSi formation but suppresses Co2Si, and delays CoSi2, which advantageously increases the silicidation-processing window. A Ti-mediated layer acting as a diffusion barrier to the supply of Co suppresses the formation of both Co2Si and CoSi but energetically favors directly forming CoSi2. Plan-view electron diffraction studies indicated that both a Ti-capped and Ti-mediated layer could be used to form ultra thin epitaxial CoSi2 silicide.

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