A Study on CVD TaN as a Diffusion Barrier for Cu Interconnects

2000 ◽  
Vol 612 ◽  
Author(s):  
Se-Joon Im ◽  
Soo-Hyun Kim ◽  
Ki-Chul Park ◽  
Sung-Lae Cho ◽  
Ki-Bum Kim

AbstractTantalum nitride (TaN) films were deposited using pentakis-diethylamido-tantalum [PDEAT, Ta(N(C2H5)2)5] as a precursor. During film growth, N- and Ar-ion beams with an energy of 120 eV were supplied in order to improve the film quality. In case of thermallydecomposed films, the deposition rate is controlled by the surface reaction up to about 350 °C with an activation energy of about 1.07 eV. The activation energy of the surface reaction controlled regime is decreased to 0.26 eV when the Ar-beam is applied. However, in case of Nbeam bombarded films, the deposition is controlled by the precursor diffusion in gas phase at the whole temperature range. By using Ar-beam, the resistivity of the film is drastically reduced from approximately 10000 µω-cm to 600 µω-cm and the density of the film is increased from 5.85 g/cm3 to 8.26 g/cm3, as compared with thermally-decomposed film. The use of N-beam also considerably lowers the resistivity of films (∼ 800 µω-cm) and increases the density of the films (7.5 g/cm3). Finally, the diffusion barrier properties of 50-nm-thick TaN films for Cu were investigated aftre annealing by X-ray diffraction analysis. The films deposited using N- and Arbeam showed the Cu3Si formation after annealing at 650 °C for 1 hour, while thermallydecomposed films showed Cu3Si peaks firstly after annealing at 600 °C. It is considered that the improvements of the diffusion barrier performance of the films deposited using N- and Ar-ion beam are the consequence of the film densification resulting from the ion bombardment during film growth.

2003 ◽  
Vol 766 ◽  
Author(s):  
Degang Cheng ◽  
Eric T. Eisenbraun

AbstractA plasma-enhanced atomic layer deposition (PEALD) process for the growth of tantalumbased compounds is employed in integration studies for advanced copper metallization on a 200- mm wafer cluster tool platform. This process employs terbutylimido tris(diethylamido)tantalum (TBTDET) as precursor and hydrogen plasma as the reducing agent at a temperature of 250°C. Auger electron spectrometry, X-ray photoelectron spectrometry, and X-ray diffraction analyses indicate that the deposited films are carbide rich, and possess electrical resistivity as low as 250νΔcm, significantly lower than that of tantalum nitride deposited by conventional ALD or CVD using TBTDET and ammonia. PEALD Ta(C)N also possesses a strong resistance to oxidation, and possesses diffusion barrier properties superior to those of thermally grown TaN.


2002 ◽  
Vol 716 ◽  
Author(s):  
H. Kim ◽  
C. Cabral ◽  
C. Lavoie ◽  
S.M. Rossnagel

AbstractTa films were grown by plasma-enhanced atomic layer deposition (PE-ALD) at temperatures from room temperature up to 300 °C using TaCl5 as source gas and RF plasma-produced atomic H as the reducing agent. Post-deposition ex situ chemical analyses showed that the main impurity is oxygen, incorporated during the air exposure prior to analysis with typically low Cl concentration below 1 at %. The X-ray diffraction indicates that ALD Ta films are amorphous or composed of nano-grains. The typical resistivity of ALD Ta films was 150-180 μΩ cm, which corresponds to that of β-Ta phase, at a wide range of growth parameters. The conformality of the film is 100 % up to an aspect ratio of 15:1 and 40 % for aspect ratio of 40:1. The thickness per cycle, corresponding to the growth rate, was measured by Rutherford back scattering as a function of various key growth parameters, including TaCl5 and H exposure time and growth temperature. The maximum thickness per cycle values were below 0.1 ML, probably due to the steric hindrance for TaCl5 adsorption. Bilayer structures consisting of Cu films deposited by sputtering and ALD Ta films with various thicknesses were prepared and the diffusion barrier properties of ALD Ta films were investigated by various analysis techniques consisting of X-ray diffraction, elastic light scattering, and resistance analysis. The results were compared with Ta thin films deposited by sputtering with comparable thicknesses. Also, the growth of TaN films by PE-ALD using consecutive exposures of atomic H and activated N2 is presented.


2013 ◽  
Vol 347-350 ◽  
pp. 1148-1152
Author(s):  
Yan Nan Zhai ◽  
Hun Zhang ◽  
Kun Yang ◽  
Zhao Xin Wang ◽  
Li Li Zhang

In order to increase the failure temperature of Zr-N diffusion barrier for Cu, the effect of insertion of a thin Zr layer into Zr-N film on Zr-N diffusion barrier performance in Cu metallization was investigated by means of X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, and 4-point probe technique. XRD,SEM ,AES and FPP results show that the insertion of a thin Zr layer into Zr-N film improves barrier properties significantly when the ZrN / Zr/ZrN barrier layers are deposited by RF reactive magnetron sputtering and Zr-N(10nm)/Zr (5nm)/Zr-N(10nm) barrier tolerates annealing at 700°C for 1 h without any breaking and agglomerating Cu film. This interpretes that insertion of a thin Zr layer into Zr-N film is attributed to the densification of grain boundaries in ZrN/Zr/ZrN films followed by the reduction of fast diffusion of Cu through ZrN /Zr/ ZrN multilayered films.


1995 ◽  
Vol 402 ◽  
Author(s):  
G. Sade ◽  
J. Pelleg

AbstractBilayer of TiB2/TiSi2 was deposited by magnetron co-sputtering on silicon and alumina substrates, and this structure was investigated for structural and electrical properties. Substrate bias and annealing in vacuum have been applied to vary the film properties. X-ray diffraction (XRD) and cross-sectional transmission electron microscopy (XTEM) were used to characterize the structure, and chemical composition was characterized by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). Resistivity was measured by four probe method. Diffusion barrier properties were studied by AES. As deposited films are amorphous with resistivities of about 40 μΩcm. Post deposition annealing in vacuum shows that the amorphous titanium boride film is very stable. Crystallization starts above 1000°C as seen by XRD, and the crystallization temperature depends on the thickness of TiB2. TiSi2 C54 forms in the temperature range 586°C - 922°C, when TiB2 still remains in amorphous form. The TiSi2 sublayer serves as an additional effective diffusion barrier, preventing outdiffusion of boron from TiB2 into the Si substrate.


2007 ◽  
Vol 26-28 ◽  
pp. 593-596 ◽  
Author(s):  
You Zhen Li ◽  
Ji Cheng Zhou

Ta-Al-N thin films on Si wafer were prepared by RF reactive magnetron sputtering in a N2/Ar ambient. Then the stacked structures of Cu/Ta-Al-N/Si were prepared and annealed at temperatures varied from 400°C to 900°C for 5 minutes in a N2 ambient tube. Four-point probe (FPP) sheet resistance measurement, Atomic force microscope (AFM), Scanning electron microscope(SEM), Alpha-Step IQ Profilers and X-ray Diffraction(XRD) were used to investigate the composition, morphology and the diffusion barrier properties of the thin films. The results show that with the increasing of Al component, the surface of Ta-Al-N thin-films became finer, the sheet resistance became higher, and after annealing at 800°C/300S FA, Cu diffusion through Ta-Al-N barrier didn’t not occurred. Results show that Ta-Al-N thin-films could act as diffusion barrier for new generation integrated circuits due to its excellent high temperature properties.


2002 ◽  
Vol 716 ◽  
Author(s):  
H. Wang ◽  
Ashutosh Tiwari ◽  
X. Zhang ◽  
A. Kvit ◽  
J. Narayan

AbstractWe have successfully grown epitaxial cubic (B1-NaCl structure) tantalum nitride films on Si (100) and (111) substrate using a pulsed laser deposition technique. A thin layer of titanium nitride was used as a buffer medium. We characterized these films using X-ray diffraction, high resolution transmission electron microscopy and scanning transmission electron microscopy (Zcontrast). X-ray diffraction and high-resolution transmission electron microscopy confirmed the single crystalline nature of these films with cubic-on-cubic epitaxy. The epitaxial relations follow TaN(100)//TiN(100)//Si(100) on Si(100) and TaN(111)//TiN(111)//Si(111) on Si(111). We observed sharp interfaces of TaN/TiN and TiN/Si without any indication of interfacial reaction. Rutherford backscattering experiments showed these films to be slightly nitrogen deficient (TaN0.95). High precision electrical resistivity measurements showed excellent metallic nature of these films. We also tried to deposit TaN directly on silicon, the films were found to be polycrystalline. In our method, TiN plays a key role in facilitating the epitaxial growth of TaN. This method exploits the concept of lattice matching epitaxy between TaN and TiN and domain matching epitaxy between TiN and Si. We studied the diffusion barrier properties of these films by growing a thin layer of copper on the top and subsequently annealing the films at 500°C and 600°C in vacuum. Cu diffusion layer was about 2nm after 600°C annealing for 30min. This work explores a promising way to grow high quality TaN diffusion barrier on silicon for copper interconnection.


2010 ◽  
Vol 74 ◽  
pp. 38-47
Author(s):  
Clay Mortensen ◽  
Paul Zschack ◽  
David C. Johnson

The evolution of designed [(Ti-Te)]x[(Sb-Te)]y, [(Bi-Te)]x[(Sb-Te)]y, [(Ti-Te)]w[(Bi-Te)]x[(Sb-Te)]y and [(Ti-Te)]w[(Bi-Te)]x[(Ti-Te)]y[(Sb-Te)]z precursors were followed as a function of annealing temperature and time using both low and high angle x-ray diffraction techniques to probe the self assembly into nanolaminate materials. The [(Bi-Te)]x[(Sb-Te)]y precursors were found to interdiffuse at low temperatures to form a (BixSb1-x)2Te3 alloy. The [(Ti-Te)]x[(Bi-Te)]y and [(Ti-Te)]x[(Sb-Te)]y precursors formed ordered nanolaminates [{(TiTe2)}1.35]x[Bi2Te3]y and [{(TiTe2)}1.35]x[Sb2Te3]y respectively. The [(Ti-Te)]w[(Bi-Te)]x[(Sb-Te)]x precursors formed [{(TiTe2)}1.35]w[(Bi0.5Sb0.5)2Te3]2x nanolaminates on annealing, as the bismuth and antimony layers interdiffused. Over the range of TiTe2 thicknesses used in [(Ti-Te)]w[(Bi-Te)]x[(Ti-Te)]y[(Sb-Te)]z precursors, Bi and Sb were found to interdiffuse through the 2-4 nm thick Ti-Te layers, resulting in the formation of (BixSb1-x)2Te3 alloy layers as part of the final nanolaminated products. When the Bi-Te and Sb-Te thicknesses were equal in the amorphous precursors, symmetric [{(TiTe2)}1.35]m[(Bi0.5Sb0.5)2Te3]n nanolamiantes were formed. When the thicknesses of Bi-Te and Sb-Te layers were not equal in the amorphous precursor, asymmetric [(TiTe2)1.35]m[(BixSb1-x)2Te3]n[(TiTe2)1.35]m[(BixSb1-x)2Te3]p nanolaminates were formed. These results imply that to form (A)w(B)x(C)y nanolaminates using designed layered precursors all three components must be immiscible. To form (A)x(B)y(A)x(C)z nanolaminates, the components must be immiscible or the precursor to the A component and the A component itself must be an effective interdiffusion barrier preventing B and C from mixing.


1995 ◽  
Vol 396 ◽  
Author(s):  
J.K.N. Lindner ◽  
B. Götz ◽  
A. Frohnwieser ◽  
B. Stritzker

AbstractWell-defined, homogenous, deep-buried 3C-SiC layers have been formed in silicon by ion beam synthesis using MeV C+ ions. Layers are characterized by RBS/channeling, X-ray diffraction, x-sectional TEM and electron diffraction. The redistribution of implanted carbon atoms into a rectangular carbon depth distribution associated with a well-defined layer during the post-implantation anneal is shown to depend strongly on the existence of crystalline carbide precipitates in the as-implanted state.


1997 ◽  
Vol 07 (03n04) ◽  
pp. 265-275
Author(s):  
R. Q. Zhang ◽  
S. Yamamoto ◽  
Z. N. Dai ◽  
K. Narumi ◽  
A. Miyashita ◽  
...  

Natural FeTiO 3 (illuminate) and synthesized FeTiO 3, single crystals were characterized by Rutherford backscattering spectroscopy combined with channeling technique and particle-induced x-ray emission (RBS-C and PIXE). The results obtained by the ion beam analysis were supplemented by the x-ray diffraction analysis to identify the crystallographic phase. Oriented single crystals of synthesized FeTiO 3 were grown under the pressure control of CO 2 and H 2 mixture gas using a single-crystal floating zone technique. The crystal quality of synthesized FeTiO 3 single crystals could be improved by the thermal treatment but the exact pressure control is needed to avoid the precipitation of Fe 2 O 3 even during the annealing procedure. Natural FeTiO 3 contains several kinds of impurities such as Mn , Mg , Na and Si . The synthesized samples contain Al , Si and Na which are around 100 ppm level as impurities. The PBS-C results of the natural sample imply that Mn impurities occupy the Fe sublattice in FeTiO 3 or in mixed phase between ilmenite and hematite.


1988 ◽  
Vol 66 (5) ◽  
pp. 373-375 ◽  
Author(s):  
C. J. Arsenault ◽  
D. E. Brodie

Zn-rich and P-rich amorphous Zn3P2 thin films were prepared by co-evaporation of the excess element during the normal Zn3P2 deposition. X-ray diffraction techniques were used to investigate the structural properties and the crystallization process. Agglomeration of the excess element within the as-made amorphous Zn3P2 thin film accounted for the structural properties observed after annealing the sample. Electrical measurements showed that excess Zn reduces the conductivity activation energy and increases the conductivity, while excess P up to 15 at.% does not alter the electrical properties significantly.


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