Stability of Sputter Deposited Al-Cu Bilayers on SiO2.

1992 ◽  
Vol 260 ◽  
Author(s):  
R. Nandan ◽  
S. P. Murarka ◽  
A. Pant ◽  
C. Shepard ◽  
W. A. Lanford
Keyword(s):  
Electrical Performance ◽  
X Ray Diffraction ◽  
Adhesion Promoter ◽  
Mos Capacitors ◽  
Rutherford Back Scattering ◽  
Cu Metallization ◽  
Bilayer Films ◽  
Sputter Deposited ◽  
The Stability ◽  
And Diffusion

ABSTRACTAn investigation of the stability and electrical characteristics of Aluminum-Copper bilayer films on SiO2 has been carried out. In this investigation, a thin layer of sputtered aluminum is used as a diffusion barrier/adhesion promoter between the copper and SiO2. The electrical performance of these structures when subjected to thermal cycles and applied biases is determined. The interactions and diffusion of copper through aluminum into SiO2 was investigated using both blanket films and MOS capacitors. Results are compared with those obtained from structures of Al and Cu metallization on SiO2. Samples were annealed at various temperatures in the range of 200°C to 500°C. Analysis using four-point probe resistivity measurements, X-ray diffraction, and Rutherford Back Scattering were carried out. MOS capacitors are used to establish performance under applied bias. Capacitance-Voltage characteristics of formed alloys are discussed. These results will be presented and discussed in view of the applicability of aluminum as the adhesion promoter for copper interconnections on SiO2.

COMPARATIVE STUDY OF IONIZED METAL PLASMA Ta, TaN AND MULTISTACKED Ta/TaN STRUCTURE AS DIFFUSION BARRIERS FOR Cu METALLIZATION

2001 ◽  
Vol 08 (05) ◽  
pp. 459-464 ◽  
Author(s):  
C. Y. LI ◽  
LEI HE ◽  
J. J. WU ◽  
Y. QIAN ◽  
L. T. KOH ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
Rutherford Back Scattering ◽  
X Ray ◽  
Force Microscopy ◽  
Barrier Materials ◽  
Cu Metallization ◽  
Atomic Force ◽  
Metal Plasma ◽  
Back Scattering ◽  
And Diffusion

The properties of the ion-metal-plasma (IMP) deposited Ta, TaN and multistacked Ta/TaN between Cu and SiO 2 have been investigated in the Cu /barrier layer/ SiO 2/ Si structures using four-point probe, atomic force microscopy (AFM), X-ray diffraction (XRD), Rutherford back scattering (RBS), tunneling electron microscopy (TEM) and metal-pulse techniques. It was found that the multistacked Ta/TaN barrier shows the best metallurgical and thermal stability among three of them, and the superior stability is found to result mainly from the nanocrystalline microstructure rather than the density and grain size of the barrier materials. The microstructure, which contains nanocrystalline grain and amorphous-like matrix, can better retard the intermixing and diffusion of Cu, Ta, O and Si atoms, due likely to reduction of grain boundaries that are the main passway for the diffusion of these elements.

Characterization of Cu-Al alloy/SiO2 interface microstructure

2000 ◽  
Vol 615 ◽  
Author(s):  
Pei-I Wang ◽  
S. P. Murarka ◽  
G.-R. Yang ◽  
E. Barnat ◽  
T.-M. Lu ◽  
...  
Keyword(s):  
Interfacial Layer ◽  
Alloy Film ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Adhesion Promoter ◽  
Adhesion Promoters ◽  
Barrier Formation ◽  
Transmission Electron ◽  
Before And After ◽  
Sputter Deposited

ABSTRACTCu-Al alloys have been recommended for application as the diffusion barriers/adhesion promoters for advanced copper based metallization schemes. This approach to barrier formation is to generate an ultra-thin interfacial layer through Cu alloying without significantly affecting the resistivity of Cu. In this paper the microstructure of the bilayers of Cu/Cu-5 at%Al and Cu-5 at%Al/Cu sputter deposited on SiO2 before and after thermal annealing is investigated by transmission electron microscopy (TEM). Interfacial layer is observed in both cases. The variation of the resistance of the Cu-Al alloy film is consistent with its microstructure. The x-ray diffraction (XRD) spectra of Cu-5 at%Al on SiO2 shows that the addition of Al into Cu intends to favor the Cu (111) texture. These results will be presented and discussed showing that films of Cu doped with Al appear to act as a suitable barrier and adhesion promoter between SiO2 and Cu.

Homogenization of the Bilayers of Cu-Al Alloy and Pure Copper to Produce CU-0.3 at.% Al Alloy Films

1998 ◽  
Vol 514 ◽  
Author(s):  
Pei-I Wang ◽  
S. P. Murarka ◽  
S. Bedell ◽  
W. A. Lanford
Keyword(s):  
Diffusion Barrier ◽  
Pure Copper ◽  
Al Alloy ◽  
Electrical Stability ◽  
Copper Metal ◽  
Adhesion Promoter ◽  
Mos Capacitors ◽  
Alloy Films ◽  
Depth Profiles ◽  
Bilayer Films

ABSTRACTPreparation of Cu-0.3 at.% Al alloy films by homogenization anneals of metallic bilayers consisting of Cu/Cu-AI on SiO2 is studied to produce advanced copper based metallization for future ICs. The bilayer films were annealed at temperature in the range of 200°C- 400°C and the depth profiles were obtained using Rutherford Backscattering technique. It is found that Al diffuses through the undoped copper layer to surface - leading to lower Al concentration in the original Al doped Cu layer and apparently increased concentration of Al in undoped Cu (not detectable by RBS). The resistivity of these annealed films ranged from 2.1 to 2.4 μΩ-cm depending on final Al concentration achieved. Electrical stability of such MOS capacitors was also investigated. All these results will be presented and discussed showing that Al-doped copper layers can be used as diffusion barrier/adhesion promoter between the oxide ILD and copper metal.

Interactions and Stability of Cu on CoSi2

1992 ◽  
Vol 260 ◽  
Author(s):  
Y. -T. Shy ◽  
S. P. Murarka ◽  
A. R. Sitaram ◽  
P.-J. Ding ◽  
W. A. Lanford
Keyword(s):  
Large Scale ◽  
Schottky Diodes ◽  
Electrical Characteristics ◽  
X Ray Diffraction ◽  
Rutherford Back Scattering ◽  
Back Scattering ◽  
Large Scale Integration ◽  
Multi Level ◽  
The Stability ◽  
Scale Integration

ABSTRACTCopper is being investigated for application as multi-level interconnection metal in silicon ultra-large-scale integration (ULSI). On the other hand, COSi2 is being tested for application as contacts in sub-half micron ULSI circuits. Copper will thus be used on COSi2 to bring the electrical connection to the outside world. In this investigation we have therefore studied the interactions of copper with CoSi2 employing sheet resistance measurements (four-point probe), Rutherford back scattering (RBS), and X-ray diffraction (XRD). In addition the stability of the Schottky diodes, n-Si/CoS2/Cu, has been investigated as a function of the heat treatment in the range of room temperature to 600° C in argon-3% hydrogen mixture gas ambient. Both the measurements of the analytical and electrical characteristics show that Cu on n-Si/CoSi2 is stable at least up to a 30 minutes anneal at 600°C in argon-3% hydrogen medium. These results will be presented and discussed.

Residual stress and microstructural evolution in thin film materials for a micro solid oxide fuel cell (SOFC).

2004 ◽  
Vol 854 ◽  
Author(s):  
David Quinn ◽  
S. Mark Spearing ◽  
Brian L. Wardle
Keyword(s):  
Residual Stress ◽  
Stress Component ◽  
Solid Oxide ◽  
Intrinsic Stress ◽  
Oxide Fuel ◽  
X Ray Diffraction ◽  
Membrane Structures ◽  
X Ray ◽  
Sputter Deposited ◽  
The Stability

ABSTRACTThe stability of multilayered membrane structures is a major challenge in the development of microfabricated solid oxide fuel cells (SOFC). The work presented here explores residual stress in sputter-deposited yttria stabilized zirconia (YSZ) thin films (5nm – 1000nm thickness) as a function of deposition pressure and substrate temperature. The results indicate variations in intrinsic stress from ∼0.5GPa compressive to mildly tensile (∼50 MPa). Microstructure is characterized by x-ray diffraction (XRD). The evolution of intrinsic stress with temperature is investigated by thermally cycling YSZ films deposited on silicon wafers. Observed changes of 100s of MPa in the intrinsic stress component of the film serve as indicators of possible changes in microstructure. Such changes in microstructure are subsequently characterized using x-ray diffraction of as-deposited and annealed films. Correlations with relevant mechanisms and models of residual stress evolution are discussed. Finally, use of such residual stress data in the fabrication and design of mechanically stable multilayered membranes for micro SOFC devices is discussed.

The Stability of MoSi2 Films in Vacuum and Oxidizing Atmospheres

1994 ◽  
Vol 357 ◽  
Author(s):  
L.E. Kolaya ◽  
D.J. Duquette ◽  
J.B. Hudson
Keyword(s):  
Mass Loss ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Post Heat Treatment ◽  
Sapphire Substrates ◽  
Approximate Composition ◽  
Treatment Analysis ◽  
Sputter Deposited ◽  
The Stability ◽  
Deposited Films

AbstractThe stability of MoSi2, films with respect to mass loss at high temperature has been investigated in vacuum and dry air environments at temperatures up to 1300° C. Samples were sputter deposited films of approximate composition MoSi3, on sapphire substrates. Post heat treatment analysis by X-ray diffraction, scanning electron microscopy, and electron microprobe analysis indicated that the films recrystallized, and that phase separation of the excess silicon from the MoSi2, occurred early in the heating process. With continued heating, silicon was lost from the films by evaporation, leading to the conversion of the films to Mo5Si3. The rate of mass loss was much less in the air environment due to the formation of a SiO2, layer which served as a diffusion barrier to silicon. Evidence of a reaction along the MoSi2,/A12O3 interface was observed visually, but could not be detected chemically.

Effective Refractory Metal Alloy Barrier Layer for High Temperature Microelectronic Device Application

2012 ◽  
Vol 1519 ◽  
Author(s):  
A.V. Adedeji ◽  
M.R. Ross ◽  
N. Hamden ◽  
A.K. Pradhan ◽  
A.C. Ahyi ◽  
...  
Keyword(s):  
Barrier Layer ◽  
Refractory Metal ◽  
Microelectronic Device ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sputter Deposited ◽  
Refractory Metal Alloy ◽  
And Diffusion

ABSTRACTThe oxidation and diffusion of Molybdenum layer sputter-deposited on 2μm CVD diamond grown on silicon substrate has been studied. The Mo layer was protected by refractory metal silicide barrier layer. The samples were annealed in air ambient at 500°C over 30 hours. The oxidation of the samples was monitored with Rutherford Backscattering Spectroscopy (RBS). The effect of reactive sputtering of refractory silicide target in argon-nitrogen gas mixture (5% nitrogen by flow rate) on the barrier characteristics was investigated. The sheet resistivity of the barrier layer on SiC substrates as a function of annealing time in air at 500°C is reported. The surface structure and morphology of the refractory silicide films was determined with X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM).

The Stability of TiH2 Used as Diffusion Barrier on SiO2 Substrates

1994 ◽  
Vol 337 ◽  
Author(s):  
Shyam P. Murarka ◽  
Sen-Hou Ko ◽  
Pei-Jun Ding ◽  
William A. Lanford
Keyword(s):  
Thin Film ◽  
Electrical Resistivity ◽  
Nuclear Reaction ◽  
Sheet Resistance ◽  
Diffusion Barrier ◽  
Water Concentration ◽  
X Ray Diffraction ◽  
Adhesion Promoter ◽  
X Ray ◽  
The Stability

ABSTRACTTiH2 has been considered as a diffusion barrier and adhesion promoter between oxide and Cu. This phase is formed by reaction of Ti with hydrogen during rapid thermal annealings. In this investigation the stability of TiH2 on PECVD and thermal oxides has been studied during Ar anneal at 400 and 500°C. X-ray diffraction, sheet resistance measurements, RBS, and nuclear reaction technique to profile hydrogen have been used in this study. The results indicate that the stability of TiH2 is dependent on the nature of the oxide, for example, the water concentration and the density of the oxide and on the temperature of the anneal. These results will be discussed in view of the applicability of TiH2 which has a low thin film electrical resistivity of about 100 μΩ-cm.

Fractionation of polymethylene chains: An electron crystallographic investigation

1986 ◽  
Vol 44 ◽  
pp. 794-795
Author(s):  
Douglas L. Dorset
Keyword(s):  
Cross Section ◽  
Binary Systems ◽  
Linear Chain ◽  
Pure Component ◽  
Organic Substrates ◽  
Crystallographic Investigation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Sizes ◽  
The Stability

A variety of linear chain materials exist as polydisperse systems which are difficultly purified. The stability of continuous binary solid solutions assume that the Gibbs free energy of the solution is lower than that of either crystal component, a condition which includes such factors as relative molecular sizes and shapes and perhaps the symmetry of the pure component crystal structures.Although extensive studies of n-alkane miscibility have been carried out via powder X-ray diffraction of bulk samples we have begun to examine binary systems as single crystals, taking advantage of the well-known enhanced scattering cross section of matter for electrons and also the favorable projection of a paraffin crystal structure posited by epitaxial crystallization of such samples on organic substrates such as benzoic acid.

TEM studies of solid-state reactions in sputter-deposited Nb/Al multilayer thin films

1996 ◽  
Vol 54 ◽  
pp. 1020-1021
Author(s):  
F. Ma ◽  
S. Vivekanand ◽  
K. Barmak ◽  
C. Michaelsen
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Stoichiometric Composition ◽  
Analytical Electron Microscopy ◽  
Grain Structure ◽  
Solid State Reactions ◽  
Multilayer Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sputter Deposited

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.

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