Thermal Stability of Thin Submicrometer Lines of CoSi2

Wang, Q. F.; Osburn, C. M.; Smith, P.; Canovai, C. A.; McGuire, G. E.

doi:10.1149/1.2056087

Cited by 43 publications

(6 citation statements)

References 4 publications

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“…Titanium was first used to form a salicide (self-aligned silicide) due to the low resistivity of TiSi2 (12-14 μΩ•cm) compared with other silicide materials. Then TiSi2 was replaced with CoSi2 because the resistance of TiSi2 had rapidly increased below the 0.3 μm technology [4,5]. But CoSi2 has also had an abrupt increase in resistance caused by void formation in narrow poly silicon gates under the 65 nm technology node.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of a nickel thin film and formation of nickel silicide by using remote plasma atomic layer deposition with Ni( i Pr-DAD)2

Kim

Jang

Park

et al. 2015

Journal of the Korean Physical Society

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In this study, the characteristics of nickel thin film deposited by remote plasma atomic layer deposition (RPALD) on p-type Si substrate and formation of nickel silicide using rapid thermal annealing were determined. Bis(1,4-di-isopropyl-1,3-diazabutadienyl)nickel, Ni( i Pr-DAD)2, was used as a Ni precursor and ammonia plasma was used as a reactant. This was the first attempt to deposit Ni thin film using Ni( i Pr-DAD)2 as a precursor for the ALD process.The RPALD Ni film was deposited with a growth rate of around 2.2Å/cycle at 250 °C and showed significant low resistivity of 33 μΩ·cm with a total impurity concentration of around 10 at. %.The impurities of the thin film, carbon and nitrogen, were existent by the forms of C-C and C-N in a bonding state. The impurities removal tendency was investigated by comparing of experimental conditions, namely process temperature and pressure. Nitrogen impurity was removed by thermal desorption during each ALD cycle and carbon impurity was reduced by the optimizing of the process pressure which is directly related with a mean free path of NH3 plasma. After Ni deposition, nickel silicide was formed by RTA in a vacuum ambient for 1 minute. A nickel silicide layer from ALD Ni and PVD Ni was compared at the annealing temperature from 500 to 900 °C. NiSi from ALD Ni showed better thermal stability due to the contribution of small amounts of carbon and nitrogen in the asdeposited Ni thin film. Degradation of the silicide layer was effectively suppressed with a use of ALD Ni.

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Section: Introductionmentioning

confidence: 99%

Characteristics of a nickel thin film and formation of nickel silicide by using remote plasma atomic layer deposition with Ni( i Pr-DAD)2

Kim

Jang

Park

et al. 2015

Journal of the Korean Physical Society

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“…The worst thermal stability problem occurs in the CoSi poly-Si structure. The CoSi film at high temperature will degrade, resulting in a dramatic increase of the sheet resistance of the film [5]. The physical process of the degradation is the thermal grooving and agglomeration of the silicide into discrete islands [6], [7].…”

Section: Introductionmentioning

confidence: 99%

Suppression of cobalt silicide agglomeration using nitrogen (N/sub 2//sup +/) implantation

Sun

Liaw

Hsu

1998

IEEE Electron Device Lett.

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In this paper, the effects of nitrogen coimplantation with boron into p + -poly gate in PMOSFET's on the agglomeration effects of CoSi2 are studied. The thermal stability of CoSi2/poly-Si stacked layers can be significantly improved by using nitrogen implantation. Samples with 40-nm Cobalt Silicide (CoSi2) on 210-nm poly-Si implanted by 2 2 10 15 /cm 2 N + 2 are thermally stable above 950 C for 30 s in N2 ambient. If the dose of nitrogen is increased up to 6 2 10 15 /cm 2 , the sheet resistance of CoSi2 film is not increased at all, and TEM photographs show that the agglomeration of CoSi 2 film is completely suppressed.

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“…4,5,[7][8][9][10][11] The motivation for this work is to understand and control the phenomenon of thinning of CoSi 2 layers at the edges adjacent to the field oxide or oxide spacer ͑positions 1 and 2 in Fig. 1, respectively͒ which were observed in the conventional process 3,12,13 and in processes where the Co layer was capped with TiN. 14,15 This thinning effect can extend to more than 100 nm from the edge, resulting in large apparent linewidth loss.…”

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confidence: 99%

“…Certainly this will be a serious problem for the silicide in deep submicrometer technology. The explanations of this thinning effect have been proposed to be due to the limited supply of Co close to the oxide edge, 3 to the possibility that Co on top of the oxide acts as a sink for the lateral diffusion of Si, 13 or to the local compressive stress near the oxide edge. 15 However, recent results by Maex et al 11,14 show that in a TiN capped process, the thinning effect is only observed at the edges with oxide but not at the edges with oxide covered by a Si 3 N 4 layer.…”

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confidence: 99%

Gaseous Impurities in Co Silicidation: Impact and Solutions

Vereecke

Maex

et al. 2001

J. Electrochem. Soc.

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With the application of a Co salicide process in deep submicrometer integrated circuits manufacturing, the potential benefit of its linewidth independent sheet resistance could be hindered due to the interaction of traces of gaseous impurities from different sources with silicide formation. In this work, we first analyze in situ the thermal desorption behavior of various dielectric and metal layers encountered in Co salicide process, by using the rapid thermal processing tool-atmospheric pressure ionization mass spectrometry. Based on these results as well as information from the literature, the detrimental impact of gaseous impurities ͑mainly O 2 and H 2 O͒ has been analyzed. The key facts are that Si has a stronger chemical affinity to O than Co, and the interaction of Co and Si oxide occurs only with great difficulty. We also argue that impurities from thermal desorption can have a stronger impact to the silicidation ͑edge thinning effect͒ compared to the impurities already in the processing ambient, due to its strong and direct interaction to the adjacent Co/Si interface. The fundamental principle of a technical solution is that the process should prevent O from coming into the Co/Si interface, and/or should be capable of removing the Si oxide already there. A few solutions reported in literature, including depositing Co at elevated temperatures, Co with reactive or nonreactive capping, and the use of Co͑Ti͒ alloys, are analyzed.

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Thermal Stability of Thin Submicrometer Lines of CoSi2

Cited by 43 publications

References 4 publications

Characteristics of a nickel thin film and formation of nickel silicide by using remote plasma atomic layer deposition with Ni( i Pr-DAD)2

Characteristics of a nickel thin film and formation of nickel silicide by using remote plasma atomic layer deposition with Ni( i Pr-DAD)2

Suppression of cobalt silicide agglomeration using nitrogen (N/sub 2//sup +/) implantation

Gaseous Impurities in Co Silicidation: Impact and Solutions

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