Amorphous Thin Film Diffusion Barriers on GaAs and InP

1982 ◽  
Vol 18 ◽  
Author(s):  
W. T. Anderson ◽  
A. Christou ◽  
J. E. Davey
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Boundaries ◽  
Ohmic Contacts ◽  
High Temperature Stress ◽  
Diffusion Barriers ◽  
Interfacial Reactions ◽  
Amorphous Thin Films ◽  
Sputter Deposited ◽  
Si Films

Thin film amorphous W-Si and TiW-Si diffusion barriers have been studied on GaAs and InP surfaces for the purpose of establishing their reliability for ohmic contacts and Schottky barriers, particularly under high temperature stress. The amorphous films were formed by a new method in which alternate layers of tungsten or TiW and silicon were sputter deposited to a total thickness of about 1300 Å and subsequently annealed near the glass transition temperature Tg(≈ 500 °C). Electron channeling and reflection electron diffraction were used to determine the amorphous nature of the films as deposited and after 4 h anneals near Tg. The as-deposited films had interfacial amorphous regions with compositions determined by interfacial reactions during the sputtering process. As-deposited W-Si films showed a weak channeling pattern which came from the unreacted polycrystalline tungsten layers. From Auger electron spectroscopy (AES) sputter profiles, it was concluded that the amorphous regions were at the W-Si interfaces which had the required tungsten-to-silicon composition ratio. After annealing at 500 °C for 4 h, the films were completely amorphous with no marked evidence of crystallization, indicating interfacial reactions extended completely into the tungsten layers. High magnification scanning electron microscopy (by a factor of 20 000) examination of the films after annealing revealed smooth and continuous surfaces with no evidence of grain boundaries. Diffusion along grain boundaries between gold and GaAs or InP in these amorphous thin films was thus almost completely eliminated. Interdiffusion of gold in layered structures (e.g. Au/(W–Si)/GaAs) was studied by AES sputter profiling techniques. No interdiffusion of gold or GaAs was observed after 16 h anneals at 400 °C. With Au/(W-Si)/InP structures, no interdiffusion was observed after 8 h anneals at 450 °C. These results are significant improvements over those for previous polycrystalline diffusion barriers (e.g. TiPt) which degrade after 1 h at 350 °C. Based on the AES sputter profiles, the diffusion coefficients in W-Si amorphous thin films were found to be less than 3 × 10−18 cm2 s−1 at 400 °C for gold, gallium and arsenic and less than 6 × 1018 cm2 s−1 at 450 °C for gold, indium and phosphorus.

Thermodynamics and Microstructure Development in the Thin Film Reaction of Aluminum on Silicon Carbide

1995 ◽  
Vol 403 ◽  
Author(s):  
T. S. Hayes ◽  
F. T. Ray ◽  
K. P. Trumble ◽  
E. P. Kvam
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Silicon Carbide ◽  
Ohmic Contacts ◽  
Microstructure Development ◽  
P Type ◽  
Microstructural Studies

AbstractA refined thernodynamic analysis of the reaction between molen Al and SiC is presented. The calculations indicate much higher Si concentrations for saturation with respect to AkC 3 formation than previously reported. Preliminary microstructural studies confirm the formation of interfacial A14C3 for pure Al thin films on SiC reacted at 9000C. The implications of the calculations and experimental observations for the production of ohmic contacts to p-type SiC are discussed.

Synthesis of Nanocomposite thin film Ti/Al Multilayers and Ti-Aluminides

1996 ◽  
Vol 457 ◽  
Author(s):  
R. Banerjee ◽  
X. D. Zhang ◽  
S. A. Dregia ◽  
H. L. Fraser
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetron Sputtering ◽  
Layer Thickness ◽  
Thermodynamic Model ◽  
Interfacial Reactions ◽  
Experimental Results ◽  
Structural Transitions ◽  
Nanocomposite Thin Film ◽  
Multilayered Thin Films

ABSTRACTNanocomposite Ti/Al multilayered thin films have been deposited by magnetron sputtering. These multilayers exhibit interesting structural transitions on reducing the layer thickness of both Ti and Al. Ti transforms from its bulk stable hep structure to fee and Al transforms from fee to hep. The effect of ratio of Ti layer thickness to Al layer thickness on the structural transitions has been investigated for a constant bilayer periodicity of 10 nm by considering three different multilayers: 7.5 nm Ti / 2.5 nm Al, 5 nm Ti / 5 nm Al and 2.5 nm Ti / 7.5 nm Al. The experimental results have been qualitatively explained on the basis of a thermodynamic model. Preliminary experimental results of interfacial reactions in Ti/Al bilayers resulting in the formation of Ti-aluminides are also presented in the paper.

Simultaneous Occurrence of Multiphases in the Interfacial Reactions of Ultrahigh Vacuum Deposited Ti, Hf and Cr Thin Films on (111)Si

1993 ◽  
Vol 311 ◽  
Author(s):  
W.W. Hsieh ◽  
J.J. Lin ◽  
M.M. Wang ◽  
L.L. Chen
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Ultrahigh Vacuum ◽  
Interfacial Reactions ◽  
Simultaneous Occurrence ◽  
Image Simulation ◽  
Reaction Sequence ◽  
Transmission Electron ◽  
Amorphous Interlayer

ABSTRACTSimultaneous occurrence of multiphases was observed in the interfacial reactions of ultrahigh vacuum deposited Ti, Hf and Cr thin films on (111)Si by high resolution transmission electron microscopy in conjunction with fast Fourier transform diffraction analysis and image simulation. For the three systems, an amorphous interlayer as well as a number of crystalline phase were found to form simultaneously in the early stages of interfacial reactions. The formation of multiphases appeared to be quite general in the initial stages of interfacial reactions of UHV deposited refractory thin films. The results called for a reexamination of generally accepted “difference” in reaction sequence between bulk and thin film couples.

Improvement of Thermal Conductivity of Electroplated Copper Thin-Film Interconnections by Controlling Their Micro Texture

2014 ◽  
Author(s):  
Pornvitoo Rittinon ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Grain Boundaries ◽  
Diffraction Method ◽  
Electron Back Scatter Diffraction ◽  
High Resistivity ◽  
Copper Thin Film ◽  
Electroplated Copper ◽  
The Relationship

Copper thin films are indispensable for the interconnections in the advanced electronic products, such as TSV (Trough Silicon Via), fine bumps, and thin-film interconnections in various devices and interposers. However, it has been reported that both electrical and mechanical properties of the films vary drastically comparing with those of conventional bulk copper. The main reason for the variation can be attributed to the fluctuation of the crystallinity of grain boundaries in the films. Porous or sparse grain boundaries show very high resistivity and brittle fracture characteristic in the films. Thus, the thermal conductivity of the electroplated copper thin films should be varied drastically depending on their micro texture based on the Wiedemann-Franz’s law. Since the copper interconnections are used not only for the electrical conduction but also for the thermal conduction, it is very important to quantitatively evaluate the crystallinity of the polycrystalline thin-film materials and clarify the relationship between the crystallinity and thermal properties of the films. The crystallinity of the interconnections were quantitatively evaluated using an electron back-scatter diffraction method. It was found that the porous grain boundaries which contain a significant amount of vacancies increase the local electrical resistance in the interconnections, and thus, cause the local high Joule heating. Such porous grain boundaries can be eliminated by control the crystallinity of the seed layer material on which the electroplated copper thin film is electroplated.

Modification of some Optical and Mechanical Properties of Amorphous As-S-Se Thin Films by Copper Introduction

2013 ◽  
Vol 856 ◽  
pp. 267-271
Author(s):  
D.D. Štrbac ◽  
G.R. Strbac ◽  
G. Stojanovic ◽  
S.R. Lukic ◽  
D.D. Petrovic
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Absorption Region ◽  
Amorphous Thin Film ◽  
Amorphous Thin Films ◽  
Single Oscillator Model ◽  
Single Oscillator ◽  
Evaporation Technique ◽  
Optical And Mechanical Properties

Abstract. In this research experimental investigation of the influence of copper introduction on some relevant parameters in As-S-Se amorphous thin films is performed. Copper is introduced into As2(S0.5Se0.5)3amorphous thin film in concentration of 3 at.%. Samples of As2(S0.5Se0.5)3and Cu3(As2(S0.5Se0.5)3)97amorphous thin films are prepared by the vacuum thermal evaporation technique from previously synthesized bulk samples. Envelope method is applied for the determination of the optical constants, using the transmission and reflection spectra. The dispersion of the refractive index is discussed in terms of the single oscillator model proposed by Wemple–DiDomenico. Values of absorption coefficients in the high absorption region are discussed according to Tauc's law.Instrumented indentation testing is performed, using the Berkovich geometry indenter, for obtaining the value of nano-hardness.All the determined parameters have shown the increase with introduction of copper into amorphous thin film.

Principal Residual Strains as A function of Depth for Sputter Deposited Mo Thin Films

1994 ◽  
Vol 356 ◽  
Author(s):  
S. G. Malhotra ◽  
Z. U. Rek ◽  
L. J. Parfitt ◽  
S. M. Yalisove ◽  
J. C. Bilello
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grazing Incidence ◽  
X Ray ◽  
X Ray Scattering ◽  
Out Of Plane ◽  
Residual Strains ◽  
Sputter Deposited ◽  
Film Substrate ◽  
Principal Strains

AbstractTraditionally, the magnitude of the stress in a thin film is obtained by measuring the curvature of the film-substrate couple; however, these techniques all measure the average stress throughout the film thickness. On a microscopic level, the details of the strain distribution as a function of depth through the thickness of the film can have important consequences in governing film quality and ultimate morphology. A new method for determining the magnitude of principal strains (strain eigenvalues) as a function of x-ray penetration depth using grazing incidence x-ray scattering for a polycrystalline thin film will be described. Results are reported for two Mo metallizations ˜ 500 Å and ˜1000 Å thick sputtered onto Si {100} substrates. The magnitude of the principal strains at several penetration depths was accomplished by an analysis of the diffraction peak shifts of at least six independent {hkl} scattering vectors from the Mo thin films. An out-of-plane strain gradient was identified in both Mo films and the strain eigenvalues were found to be anisotropic in nature. This new methodology should work with a variety of thin films and hence would provide quantitative insight into the evolution of thin film microstructure.

Irradiation Effect on Ta2O5 Thin Films

2014 ◽  
Vol 353 ◽  
pp. 205-210
Author(s):  
N. Baydogan ◽  
B. Erkan ◽  
A.B. Tugrul ◽  
Huseyin Cimenoglu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Radiation Dose ◽  
Grain Boundaries ◽  
Absorbed Dose ◽  
Irradiation Effect ◽  
Long Term Effects ◽  
Irradiation Treatment ◽  
Dose Levels ◽  
Irradiation Process

Long-term effects of time-dependent solarization behavior on optical density and optical band gap of the gamma and beta irradiated Ta2O5 thin films were investigated to examine the optical aging of films at different absorbed dose levels. Irradiation process caused to induce defect centres. The population inversion of the colour centres was increased by controlling the absorbed dose at certain radiation dose levels. The efficient absorption of photons in tantalum reduced transmittance. The grain boundaries of the Ta2O5 thin film decreased at the end of irradiation process. The average grain boundaries changed after the irradiation process at 4.5 kGy and average grain boundaries decreased from ~ 11.5 to 5.5 μm. The optical fading behavior of induced color centers addressed to the potential opportunities of Ta2O5 thin film by monitoring absorption of photons in optoelectronic technology. Optical fading of the Ta2O5 thin film presented an importance to investigate the material stored ionizing radiation dose in it with the increase of elapsed time after the irradiation treatment.

Crystallinity Control of Electroplated Interconnections for Improving Their Stability and Lifetime

2016 ◽  
Author(s):  
Jiatong Liu ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Grain Boundaries ◽  
Lattice Mismatch ◽  
Bulk Material ◽  
Chemical Properties ◽  
Mechanical Fracture ◽  
Copper Thin Film ◽  
Electroplated Copper

In a three-dimensional (3D) packaging systems, the interconnections which penetrate stacked silicon chips have been employed. Such interconnection structure is called TSV (Through Silicon Via) structure, and the via is recently filled by electroplated copper thin film. The electroplated copper thin films often consist of fine columnar grains and porous grain boundaries with high density of defects which don’t appear in conventional bulk material. This unique micro texture has been found to cause the wide variation of physical and chemical properties of this material. In the TSV structure, the shrinkage of the copper thin film caused by thermal deformation and recrystallization of the unique texture during high-temperature annealing is strictly constrained by surrounding rigid Si and thus, high tensile residual stress remains in the thin film after thermal annealing. High residual stress should give rise to mechanical fracture of the interconnections and the shift of electronic function of thin film devices formed in Si. Therefore, the residual stress in the interconnections should be minimized by controlling the appearance of the porous boundaries during electroplating for assuring the longterm reliability of the interconnections. As the lattice mismatch between Cu and its barrier film (Ta) is as larger as 18%, which is the main reason for the fine columnar structures and porous grain boundaries, it is necessary to control the underlayer crystallinity to improve the crystallinity of electroplated copper thin films. In this study, the effective method for controlling the crystallinity of the underlayer was investigated by improving the atomic configuration in the electroplated copper thin film. The result showed that by controlling the crystallinity of underlayer, crystallinity of electroplated copper thin films can be improved, the mechanical properties of thin films was improved and thus, stability and lifetime of electroplated copper interconnections can be improved.

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