Partial agglomeration during Co silicide film formation

1992 ◽  
Vol 7 (2) ◽  
pp. 269-272 ◽  
Author(s):  
Z.G. Xiao ◽  
G.A. Rozgonyi ◽  
C.A. Canovai ◽  
C.M. Osburn
Keyword(s):  
Phase Transformation ◽  
Theoretical Model ◽  
Film Formation ◽  
Main Body ◽  
Volume Changes ◽  
Silicide Film ◽  
Resistivity Measurements ◽  
Si Substrates ◽  
Silicide Layer ◽  
Kirkendall Voids

The agglomeration of Co silicide films formed on Si substrates processed with evaporated Co film thicknesses from 9 to 28 nm was investigated by TEM and four-point-probe resistivity measurements. It was found that the upper portion of a reacting Co or Co silicide film can agglomerate independently from the main body of the silicide layer. This phenomenon is designated partial agglomeration in contrast to whole film agglomeration which generally occurs at higher temperatures. Partial agglomeration appears to develop more extensively for thinner films and poses a serious limitation for the application of thin silicide contact layers for advanced VLSI devices. The formation mechanism of partial agglomeration and the reason for its variation with film thickness are explained on the basis of a previously presented [MRS Proc. Vol. 202, p. 101 (1991)] theoretical model of grain boundary grooving and the onset of islanding in silicide films. Kirkendall voids and phase transformation induced volume changes play an important role in the process.

Electronic Properties of Bismuth Nanowires

2001 ◽  
Vol 679 ◽  
Author(s):  
Stephen B. Cronin ◽  
Yu-Ming Lin ◽  
Oded Rabin ◽  
Marcie R. Black ◽  
Gene Dresselhaus ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Band Structure ◽  
Temperature Dependence ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Temperature Dependent ◽  
Si Substrates ◽  
Bismuth Nanowires ◽  
Bi Nanowire ◽  
Anodic Alumina Templates

ABSTRACTThe pressure filling of anodic alumina templates with molten bismuth has been used to synthesize single crystalline bismuth nanowires with diameters ranging from 7 to 200nm and lengths of 50μm. The nanowires are separated by dissolving the template, and electrodes are affixed to single Bi nanowires on Si substrates. A focused ion beam (FIB) technique is used first to sputter off the oxide from the nanowires with a Ga ion beam and then to deposit Pt without breaking vacuum. The resistivity of a 200nm diameter Bi nanowire is found to be only slightly greater than the bulk value, while preliminary measurements indicate that the resistivity of a 100nm diameter nanowire is significantly larger than bulk. The temperature dependence of the resistivity of a 100nm nanowire is modeled by considering the temperature dependent band parameters and the quantized band structure of the nanowires. This theoretical model is consistent with the experimental results.

SUPERCONDUCTING PROPERTIES OF (Tl0.64Bi0.16Pb0.2)Ba2−xSrxCa3Cu4Oy BY LIQUID-GAS-SOLIDIFICATION PROCESSING

1991 ◽  
Vol 05 (26) ◽  
pp. 1735-1743
Author(s):  
H. CHOU ◽  
H.S. CHEN ◽  
E.M. GYORGY ◽  
A.R. KORTAN ◽  
L.C. KIMERLING ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Solidification Process ◽  
Tetragonal Structure ◽  
Layer Formation ◽  
Superconducting Properties ◽  
Solidification Processing ◽  
Resistivity Measurements ◽  
Percolation Limit ◽  
Non Equilibrium

The effect of Sr substitution in (Tl0.64Bi0.16Pb0.2)Ba2−xSrxCa3Cu4Oy(x=0, 1, 2) superconductors is studied by liquid-gas-solidification process. (Tl0.64Bi0.16Pb0.2)Ba2−x SrxCa3Cu4Oy forms a tetragonal structure, with a c axis decreasing with Sr content. The substitution of Sr tends to suppress Cu-O layer formation. It also slows down the phase transformation from Tl-rich to Tl-poor phases which may be attributed to a phase equilibration of kinetic origin. The superconducting crystals grow under non-equilibrium and anisotropic conditions, and exhibit platelet and dentritic morphologies. The resistivity measurements indicate percolation effects with a percolation limit of just above 8% of the high Tc phase.

Ultrathin cobalt silicide film formation on Si(100)

2003 ◽  
Vol 35 (2) ◽  
pp. 184-187 ◽  
Author(s):  
I. Y. Hwang ◽  
J. H. Kim ◽  
S. K. Oh ◽  
H. J. Kang ◽  
Y. S. Lee
Keyword(s):  
Film Formation ◽  
Cobalt Silicide ◽  
Silicide Film

Thermal Stability of CoSi2 on Single Crystal and Polycrystalline Silicon

1990 ◽  
Vol 182 ◽  
Author(s):  
J. R. Phillips ◽  
P. Revesz ◽  
J. O. Olowolafe ◽  
J. W. Mayer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Single Crystal ◽  
Polycrystalline Silicon ◽  
Sheet Resistivity ◽  
X Ray ◽  
Resistivity Measurements ◽  
Silicide Layer ◽  
Thermal Stability Of ◽  
Scanning Electron

AbstractThe thermal stability of Co silicide on single crystal and polycrystalline Si has been investigated. Co films were evaporated onto (100) Si and undoped polycrystalline Si and annealed in vacuum. Resulting silicide films were examined using Rutherford backscattering spectroscopy, scanning electron microscopy, electron—induced x—ray spectroscopy, and sheet resistivity measurements. We find that CoSi2 on single crystal (100) Si remains stable through 1000ºC. In contact with undoped polycrystalline Si, intermixing begins at temperatures as low as 650ºC for 30min annealing. The Co silicide and Si layers are intermixed after 750ºC 30min annealing, giving islands of Si surrounded by silicide material, with both components extending from the surface down to the underlying oxide layer. The behavior of CoSi2 contrasts with results reported for TiSi2 which agglomerates on single crystal Si around 900ºC but is stable on polycrystalline silicon as high as 800ºC. Resistivity measurements show that the Co silicide remained interconnected despite massive incursion by Si into the silicide layer.

Investigation of an in-situ probe for phase transformations during RTP silicidation

1992 ◽  
Vol 260 ◽  
Author(s):  
R. J. Schreutelkamp ◽  
P. Vandenabeele ◽  
B. Deweerdt ◽  
W. Coppye ◽  
C. Vermeiren ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Thermal Degradation ◽  
Phase Transformations ◽  
Doping Level ◽  
Polycrystalline Silicon ◽  
Silicon Substrates ◽  
Si Substrates ◽  
Background Doping ◽  
Emissivity Measurements

ABSTRACTIn-situ emissivity measurements at a wavelength of 2.4 μα were used to monitor RTP Co silicidation on crystalline and polycrystalline silicon substrates. The influence of various parameters influencing the silicidation reaction was extensively studied. It is shown that particularly the phase transformation from CoSi to the final suicide phase, COSi2, strongly depends on parameters such as background doping level and type of substrate. This is illustrated for As-doped substrates. The method is extremely sensitive for the in-situ detection of the thermal degradation of thin COSi2 films at high temperatures, which is demonstrated for 25 nm COSi2 layers on highly As-doped c-Si substrates.

Arsenic Diffusion and Segregation Behavior at the Interface of Epitaxial CoSi2 Film and Si Substrate

1993 ◽  
Vol 320 ◽  
Author(s):  
S. L. Hsia ◽  
T. Y. Tan ◽  
P. L. Smith ◽  
G. E. Mcguire
Keyword(s):  
Qualitative Agreement ◽  
Film Formation ◽  
Formation Temperature ◽  
Si Substrate ◽  
Free Surfaces ◽  
Si Substrates ◽  
Segregation Behavior ◽  
P Type ◽  
Physical Reasons ◽  
Source Materials

ABSTRACTArsenic diffusion and segregation properties at the interface of the epitaxial CoSi2 and Si substrate have been studied. Samples have been prepared using Co-Ti bimetallic source materials and two types of (001) Si substrates: n+ (doped by As to ∼2}1019 cm−3) and p. For the n+ Si cases, the lower limit of the CoSi2 film formation temperature is increased by ∼200°C to ∼700°C. SIMS results showed As segregation into Si. For epitaxial CoSi2 film formation at 900°C, the As concentration has increased by a factor of ∼2 within a distance of ∼30nm from the interface, while the incorporated As in the film is ∼30-50 times less than that in Si. For p-type Si substrate cases, the epitaxial CoSi2 film was first grown and followed by As+ implantation (into the film) and drive-in processes. It is observed that As was segregated to the CoSi2-Si interface and diffused into Si. This is in qualitative agreement with our results obtained from the n+ substrate experiments and the results of other authors involving the use of polycrystalline CoSi2 films. In the present cases, all implanted As were conserved at a drive in-temperature of 1000°C for up to 100 s. This is in contrast to the polycrystalline CoSi2 film results which involve a substantial As loss to the film free surfaces. The physical reasons of this difference have been discussed.

Formation Mechanism of Epitaxial CoSi2 Films on (001) Si Using Ti-Co Bimetallic Layer Source Materials

1992 ◽  
Vol 280 ◽  
Author(s):  
S. L. Hsia ◽  
T. Y. Tana ◽  
P. L. Smith ◽  
G. E. Mcguire
Keyword(s):  
Film Formation ◽  
Substrate Surface ◽  
Native Oxide ◽  
Formation Processes ◽  
Mechanism Of Formation ◽  
Si Substrate ◽  
Barrier Material ◽  
Si Substrates ◽  
Bimetallic Layer ◽  
Source Materials

ABSTRACTThe mechanism of formation of epitaxial CoSi2 film on (001) Si substrate, produced using sequentially deposited Ti-Co bimetallic layer source materials for which Ti was deposited onto the Si substrates first, has been studied by observing the Co silicide formation processes and structures in samples prepared by isochronal annealing and by isothermal annealing. The results demonstrated that, in leading to epitaxial CoSi2 film formation, Ti has played two roles. It has served as a barrier material to Co atoms and thus preventing Co2Si from forming. More importantly, it has allowed nucleation and growth of epitaxial-CoSi2 to dominate the Co silicide film formation process, apparently because it has served as a cleanser to remove native oxide from the Si substrate surface.

Enhancement of Aurivillius Phase Formation Kinetics in SBT Thin Films using Nanoparticle Seeding

2003 ◽  
Vol 784 ◽  
Author(s):  
Yun-Mo Sung ◽  
Woo-Chul Kwak ◽  
Se-Yon Jung ◽  
Seung-Joon Hwang
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Phase Transformation ◽  
Phase Formation ◽  
X Ray Diffraction ◽  
Aurivillius Phase ◽  
X Ray ◽  
Si Substrates ◽  
Formation Kinetics ◽  
Kinetics Of

ABSTRACTPt/Ti/SiO2/Si substrates seeded by SBT nanoparticles (∼60–80 nm) were used to enhance the phase formation kinetics of Sr0.7Bi2.4Ta2O9 (SBT) thin films. The volume fractions of Aurivillius phase formation obtained through quantitative x-ray diffraction (Q-XRD) analyses showed highly enhanced kinetics in seeded SBT thin films. The Avrami exponents were determined as ∼1.4 and ∼0.9 for unseeded and seeded SBT films, respectively, which reveals different nucleation modes. By using Arrhenius–type plots the activation energy values for the phase transformation of unseeded and seeded SBT thin films were determined to be ∼264 and ∼168 kJ/mol, respectively. This gives a key reason to the enhanced kinetics in seeded films. Microstructural analyses on unseeded SBT thin films showed formation of randomly oriented needle-like crystals, while those on seeded ones showed formation of domains comprised of directionally grown worm-like crystals.

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