Ultra-Thin TaN Films As Diffusion Barriers For Cu Metallization

1998 ◽  
Vol 514 ◽  
Author(s):  
Sharon S. Huang ◽  
K. N. Tu ◽  
Bingxi Sun
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Diffusion Barrier ◽  
Large Data ◽  
Cu Films ◽  
Cu Metallization ◽  
Transmission Electron ◽  
Vlsi Technology ◽  
Electron Microscopes ◽  
20 Nm

ABSTRACTThe Cu metallization in future VLSI technology requires a liner or diffusion barrier. We have studied TaN thin Films of thickness from 5 nm to 3 nm as the diffusion barrier. We deposited sandwiched TaN/Cu/TaN thin films on oxidized Si wafers, annealed them in air with ramping temperature, and measured in-situ resistance changes. Scanning and transmission electron microscopes were used to characterize the surface and microstructure of the thin films and Rutherford backscattering spectrometer (RBS) was used to profile the elemental composition and after oxidation. The oxidation of the Cu sandwiched between TaN films of 5, 10, 20, and 30 nm occurs at 300, 400, 450 and 475°C, respectively. The activation energy of oxidation of Cu with the TaN barrier of 10, 20, and 30 nm are 1.73, 2.13, and 2.26 eV, respectively, but the 5 nm TaN was not calculated due to large data scattering. For comparison, the oxidation temperature and activation energy for bare Cu films in air are 250°C and 0.74 eV, respectively. It suggests that 20 nm of TaN is quite effective as a barrier layer. However, the reaction between Cu and the underlying SiO2/Si layers was also detected in RBS; this may arise as another serious reliability criterion to the system.

Structural and Electrical Characterization of Si-Implanted TiN as a Diffusion Barrier for Cu Metallization

1995 ◽  
Vol 391 ◽  
Author(s):  
W.F. Mcarthur ◽  
K.M. Ring ◽  
K.L. Kavanagh
Keyword(s):  
Leakage Current ◽  
Diffusion Barrier ◽  
Depth Profiling ◽  
Electrical Characterization ◽  
Implantation Dose ◽  
Cu Metallization ◽  
Reverse Leakage Current ◽  
Transmission Electron ◽  
Current Voltage

AbstractThe feasibility of Si-implanted TiN as a diffusion barrier between Cu and Si was investigated. Barrier effectiveness was evaluated via reverse leakage current of Cu/TixSiyNz/Si diodes as a function of post-deposition annealing temperature and time, and was found to depend heavily on the film composition and microstructure. TiN implanted with Si28, l0keV, 5xl016ions/cm2 formed an amorphous ternary TixSiyNz layer whose performance as a barrier to Cu diffusion exceeded that of unimplanted, polycrystalline TiN. Results from current-voltage, transmission electron microscopy (TEM), and Auger depth profiling measurements will be presented. The relationship between Si-implantation dose, TixSiyNz structure and reverse leakage current of Cu/TixSiyNz/Si diodes will be discussed, along with implications as to the suitability of these structures in Cu metallization.

Mechanisms of misfit strain relaxation in epitaxially grown BLT (Bi4-xLaxTi3O12, x = 0.75) thin films

2003 ◽  
Vol 779 ◽  
Author(s):  
Hyung Seok Kim ◽  
Sang Ho Oh ◽  
Ju Hyung Suh ◽  
Chan Gyung Park
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Strain Relaxation ◽  
Lattice Misfit ◽  
Misfit Strain ◽  
Misfit Dislocations ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
20 Nm

AbstractMechanisms of misfit strain relaxation in epitaxially grown Bi4-xLaxTi3O12 (BLT) thin films deposited on SrTiO3 (STO) and LaAlO3 (LAO) substrates have been investigated by means of transmission electron microscopy (TEM). The misfit strain of 20 nm thick BLT films grown on STO substrate was relaxed by forming misfit dislocations at the interface. However, cracks were observed in 100 nm thick BLT films grown on the same STO. It was confirmed that cracks were formed because of high misfit strain accumulated with increasing the thickness of BLT, that was not sufficiently relaxed by misfit dislocations. In the case of the BLT film grown on LAO substrate, the magnitude of lattice misfit between BLT and LAO was very small (~1/10) in comparison with the case of the BLT grown on STO. The relatively small misfit strain formed in layered structure of the BLT films on LAO, therefore, was easily relaxed by distorting the film, rather than forming misfit dislocations or cracks, resulting in misorientation regions in the BLT film.

Diffusion Characteristics of Cu in TiN Thin Films

2001 ◽  
Vol 686 ◽  
Author(s):  
Abhishek Gupta ◽  
Hiyan Wang ◽  
Alex V. Kvit ◽  
Gerd Duscher ◽  
Jay Narayan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Diffusion Barrier ◽  
Pulse Laser Deposition Technique ◽  
Structure Property ◽  
Contrast Imaging ◽  
Transmission Electron ◽  
Diffusion Characteristics ◽  
Tin Thin Films

AbstractWe have investigated the diffusion characteristics of Cu in nanocrystalline, polycrystalline and single crystal TiN thin films, which are being used as a diffusion barrier for sub-quarter-micron metallization. These films were synthesized on Si (100) substrate by first ablating TiN and then ablating Cu targets using Pulse Laser Deposition technique. The three different microstructures of TiN were achieved by growing the films at different substrate temperatures, where higher temperatures (650 °C) leads to epitaxy. Then a uniform thin layer of Cu was deposited on TiN/Si substrate at room temperature for all the three depositions above. These structures were characterized using X-Ray diffraction technique and high-resolution transmission electron microscopy. Each sample is then annealed at 500 °C for 30min to study the diffusion barrier characteristics as a function of microstructure of TiN. Study of diffusion profile and Cu concentration measurement were performed using Scanning Transmission Electron Microscopy-Z contrast Imaging (0.12nm resolution), Electron Energy Loss Spectroscopy and Secondary Ion Mass Spectroscopy. From the results obtained the effect of microstructure of TiN thin films on the diffusion characteristics of Cu after annealing was analyzed. Four points probe resistivity measurements were made to establish structure property correlations.

Stress evolution in passivated thin films of Cu on silica substrates

1998 ◽  
Vol 13 (7) ◽  
pp. 1928-1937 ◽  
Author(s):  
Y-L. Shen ◽  
S. Suresh ◽  
M. Y. He ◽  
A. Bagchi ◽  
O. Kienzle ◽  
...  
Keyword(s):  
Thin Films ◽  
Strain Hardening ◽  
Shear Bands ◽  
Back Stress ◽  
Constitutive Law ◽  
Temperature Dependent ◽  
Cu Films ◽  
Transmission Electron ◽  
Stress Transmission ◽  
Very High

Stresses supported by thin films of Cu passivated by SiOx have been measured upon thermal cycling. Very high stresses have been found, approaching 1 GPa in the thinnest (40 nm) films. Strengthening beyond yield occurs upon both cooling and heating, indicative of strong strain hardening in the Cu. The hardening continues down to at least 77 K. The yielding behavior of the Cu films has been characterized by a kinematic constitutive law, with exceptional strain hardening and a conventional temperature-dependent yield strength. The physical basis for this behavior is ascribed to confined shear bands in the Cu that induce large back stress. Transmission electron microscopy reveals aligned dislocations, which seemingly dictate the inelastic deformations in the shear bands.

A Comparison of AFM, SEM, and TEM Analysis of AL/SI/CU Thin Films

1992 ◽  
Vol 260 ◽  
Author(s):  
K. L. Westra ◽  
D. J. Thomson
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Finite Size ◽  
Sem Analysis ◽  
Tem Analysis ◽  
Cu Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Sputter Deposited

ABSTRACTAtomic Force microscopy, scanning electron microscopy, and transmission electron microscopy was used to study Al/Si/Cu films sputter deposited at 2 and 45 mTorr. AFM and SEM analysis shows the films to consist of columnar structures commonly seen in PVD deposited thin films, while the TEM analysis showed the films be polycrystalline. Comparing the columnar structures seen in the AFM and SEM study to the grains found in the TEM study, we conclude that the columns consist of single grains. Thus for these films AFM or SEM analysis can be used to determine the grain size. Finally, an AFM scan of a Al/Si/Cu deposited via was performed. The AFM image clearly shows the high resolution of the AFM, while it also illustrates the problems caused by the finite size of the AFM tip.

Abnormal grain growth of sputtered CuNi(Mn) thin films

2000 ◽  
Vol 15 (5) ◽  
pp. 1062-1068 ◽  
Author(s):  
W. Brückner ◽  
V. Weihnacht ◽  
W. Pitschke ◽  
J. Thomas ◽  
S. Baunack
Keyword(s):  
Thin Films ◽  
Grain Growth ◽  
Abnormal Grain Growth ◽  
Temperature Cycle ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Columnar Grains ◽  
Maximum Temperatures ◽  
Film Substrate ◽  
20 Nm

The evolution in both stress and microstructure was investigated on sputtered Cu0.57Ni0.42Mn0.01thin films of 400 nm thickness during the first temperature cycle up to 550 °C. Samples from stress–temperature measurements up to various maximum temperatures were analyzed by x-ray diffraction, scanning and transmission electron microscopy, and Auger electron spectroscopy. The columnar grains with lateral diameters of about 20 nm in the as-deposited state coarsen to about 400 nm above 300 °C. Probably due to the impurity (Mn) drag effect, the coarsening occurs by abnormal grain growth rather than by normal grain growth, starting near the film–substrate interface. The stress development results from a combination of densification due to grain growth and plastic stress relaxation.

Domain structures in Pb(Zr, Ti)O3 and PbTiO3 thin films

1997 ◽  
Vol 12 (10) ◽  
pp. 2612-2616 ◽  
Author(s):  
L. D. Madsen ◽  
E. M. Griswold ◽  
L. Weaver
Keyword(s):  
Thin Films ◽  
Classification Scheme ◽  
Sol Gel ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Grain Sizes ◽  
Domain Structures ◽  
Transmission Electron ◽  
20 Nm ◽  
Gel Processing

The microstructure of Pb(Zr, Ti)O3 (PZT) and PbTiO3 (PT) thin films deposited by the sol-gel method and chemical vapor deposition, respectively, were examined by transmission electron microscopy (TEM). Domains with ∼7 and ∼20 nm widths were found for the PZT and PT thin films, respectively. The traditional parallel twin or wedge-type structures found in bulk ceramics have been observed in thin films. Differences between observed grain sizes and previous studies of similar compounds (in bulk form) are accounted for by geometrical considerations related to crystallographic factors. Finally, a classification scheme for domains in PZT and PT thin films based on these and other published results of several researchers is presented. Domain sizes varied according to three categories: mono-domains (2–50 nm in diameter), domains in spherulite lamellae (28–130 nm wide), and twins in conventional large grains (5–150 nm wide). The mono-domains are related to small grain sizes, while the lamellae are a function of the nucleation and growth associated with sol-gel processing.

Properties of Cu3Ge Films for Contacts to Si and SiGe and Cu Metallization

1998 ◽  
Vol 514 ◽  
Author(s):  
Mark A. Borek ◽  
S. Oktyabrsky ◽  
M. O. Aboelfotoh ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Secondary Ion Mass Spectrometry ◽  
Temperature Oxidation ◽  
Polycrystalline Layer ◽  
Cu Metallization ◽  
Transmission Electron ◽  
Abrupt Interface ◽  
Pure Cu

ABSTRACTWe have formed thin films of Cu3Ge on (100) Si and (100) Si50Ge50 for low resistivity ohmic contacts and interconnects by the sequential room temperature e-beam deposition of a layer of amorphous Ge, followed by a polycrystalline layer of Cu. We have also deposited thin films of Cu on the Si50Ge50 to compare the behavior of films of Cu3Ge relative to that of pure Cu. We have determined by transmission electron microscopy (TEM) that films of Cu3Ge form an abrupt interface with Si and Si50Ge50, with no indication of interaction between the film and substrate. We have also shown by secondary ion mass spectrometry (SIMS) that Cu diffusion into the underlying substrate is not observed for films of Cu3Ge as compared to that of pure Cu. We have shown that Cu reacts with Si50Ge50 when annealed or 30 min. at 400°C to form a layer of Cu3Si1−xGe.. We have also observed that room temperature oxidation of the underlying Si50Ge50 does not occur as compared to the room temperature formation of SiO2 that is observed in Cu3Si/Si structures.

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