Grain boundary diffusion effects on the sputter depth profiles of Co–Ag bilayers

Lee, Y. S.; Choi, In–Hoon; Lim, Kee Young; Jeong, Kyu Shik; Whang, C. N.; Choe, H.S.; Lee, Y. P.

doi:10.1063/1.361405

Cited by 7 publications

(6 citation statements)

References 16 publications

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“…Figure 5 shows the TiN layer thickness dependence on atomic fraction σ at elevated temperatures. When we assume that the accumulated Cu atoms are uniformly distributed in the surface region, that the probability of a Cu atom finding a vacant surface site is proportional to the fraction of the surface which is not yet covered with Cu, the top-layer thickness dependence of the accumulation surface concentration can be described as [14,17] σ = 1 − exp − P l (4) Fig. 5.…”

Section: Resultsmentioning

confidence: 99%

“…To study this grain boundary diffusion (GBD) in thin films at low temperatures, the surface accumulation [15][16][17] and depth profiling [18,19] have been the most commonly used methods in highly sensitive surface analytical techniques, such as Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS), and X-ray photoelectron spectroscopy (XPS). The surface accumulation method has many advantages over the depth profiling method; it is more sensitive to the details of the source, and the surface sink conditions at the grain boundaries are required to produce a measurable concentration on the accumulation surface.…”

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confidence: 99%

“…The surface accumulation method has many advantages over the depth profiling method; it is more sensitive to the details of the source, and the surface sink conditions at the grain boundaries are required to produce a measurable concentration on the accumulation surface. The surface accumulation method is useful for the top-layer materials which formed a layer in surfaces such as Ag [17]. However, in the case of Cu which is agglomerated in the surface during annealing [6], the modified surface accumulation method (a kind of surface accumulation method using depth profiling) [14,20] is more useful.…”

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confidence: 99%

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Grain boundary diffusion of Cu in TiN film by X-ray photoelectron spectroscopy

Lim

Lee

Chung

et al. 2000

Applied Physics A: Materials Science & Processing

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In this study, the grain boundary diffusion of Cu through a TiN layer with columnar structure was investigated by X-ray photoelectron spectroscopy (XPS). It was observed that Cu atoms diffuse from the Cu layer to the surface along the grain boundaries in the TiN layer at elevated temperature. In order to estimate the grain boundary diffusion constants, we used the surface accumulation method. The diffusivity of Cu through TiN layer with columnar structure from 400The present semiconductor devices such as ULSI require the higher integration density with smaller submicron design scheme. However, aluminum and aluminum-based metallization have some problems such as the relatively higher resistance and the failure caused by the electromigration. At present, Cu has attracted more attention as a new interconnection metallization material, because of its low resistivity (1.67 µΩ cm for bulk), and high reliability against electromigration (EM) [1,2]. However, Cu is regarded as a fatal impurity in the semiconductor fabrication process due to its high diffusivity in Si (diffusion coefficient ≈ 10 −8 cm 2 /s at room temperature) [3][4][5]. Therefore, a thin diffusion barrier preventing Cu diffusion in Si substrate is needed in order to successfully integrate Cu as an interconnecting layer.TiN is one of the most widely investigated barrier materials in Cu metallization, as well as in Al-based metallization. Thus, there are many reports for the Cu diffusion in TiN during the annealing even though the failure temperatures of TiN against Cu diffusion differ among researchers [6-10]. Generally, it was known that the grain boundaries of TiN film act as a main diffusion path of Cu or Si [8]. Therefore, to understand the temperature failure mechanisms of TiN against Cu, an investigation of the diffusivity and diffusion mechanisms of Cu in TiN thin film are needed.From the results of Chamberlain [11], the grain boundary diffusivity (D b ) and the activation energy (Q b ) of Cu in the Cu/TiN/sapphire system were 10 −17 -10 −19 cm 2 /s and 4.4 eV, respectively, at temperature region from 600 • C to 700 • C. His results indicate that TiN in Cu metallization is a better barrier system than that in Al metallization since Q b and D b of Al through TiN layer were 0.31 eV and ≈ 10 −16 cm 2 /s, respectively, from 300 • C to 550 • C [12]. Although the differences in failure temperatures and diffusion coefficients are caused by various film microstructures and characterization methods, the grain boundary diffusion coefficients of Chamberlain [11], are too different from those of Al through TiN layer. In general, the value of Q b is approximately half of that for lattice diffusion [13] and in the range of T < 1 3 T m , the smaller the measurement temperature T is, the smaller the value of Q b should be [14]. Therefore, his values of diffusion coefficient seem to be unreasonable from a view point of the grain boundary diffusion. In fact, his Q b , 4.4 eV, for Cu in TiN layer is closed to the value of the bulk (=lattice) diffusion.To study this gr...

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Section: Resultsmentioning

confidence: 99%

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Grain boundary diffusion of Cu in TiN film by X-ray photoelectron spectroscopy

Lim

Lee

Chung

et al. 2000

Applied Physics A: Materials Science & Processing

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“…Lee et al [11] investigated the grain boundary diffusion (GBD) process of Co/Ag bilayer on oxidized Si wafer. They found that the Ag atoms diffuse along the grain boundaries through the Co layer to the surface, and then spread out along the surface to accumulate 2-3 ML Ag on Co layer in a layer-by-layer growth mode.…”

Section: Resultsmentioning

confidence: 99%

Enhancement of magneto-optical Kerr effect for Co ultra-thin film on Pt(111) with Ag buffer layer

Tzeng

et al. 2004

Journal of Magnetism and Magnetic Materials

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“…According to our knowledge, in the literature only one article reports this phenomenon [13]. The grain boundary diffusion is described in several immiscible systems [14][15][16].…”

Section: Introductionmentioning

confidence: 99%