Au and Al interface reactions with SiO2

Bauer, R. S.; Bachrach, R. Z.; Brillson, L. J.

doi:10.1063/1.91720

Cited by 85 publications

(35 citation statements)

References 27 publications

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“…At lower voltages the current would be lower due to the thicker equivalent thickness, but higher when injection is above the lower barrier. In this case a likely candidate for the low barrier dielectric would be Al 2 O 3 since it is well known that SiO 2 is reduced into Al 2 O 3 through the chemical reaction [24][25][26][27][28][29] 3SiO 2 ϩ 4Al r 2Al 2 O 3 ϩ 3Si [14] This is also supported by the fact that of the included gate materials in our study only Al-gated devices show any increase in the capacitance (Fig. 5).…”

supporting

confidence: 75%

Electrical Characterization of Interfacial Reactions in Ultrathin Oxides during Postmetalization Anneal

Ragnarsson

Aderstedt

Lundgren

1999

J. Electrochem. Soc.

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The quest to find a replacement for the traditional dielectric used in the semiconductor industry, namely, SiO 2 , is attracting an increasing amount of research. As demands for faster and less power consuming electronic devices continue to increase, device dimensions and supply voltages together with a number of other parameters are forced to lower values. In not more than 15 years the equivalent gate dielectric thickness is predicted to be as low as 10 Å. 1 If such extremely thin gate dielectrics were to consist solely of SiO 2 , the leakage current through the gate would be intolerable. 1 The main objective of research in this area is therefore to find a way to maintain or increase control of the inversion channel from the gate with decreasing voltages without increasing the leakage current through the gate dielectric. A possible solution is to replace part of the SiO 2 with a dielectric with higher permittivity thus increasing the capacitance while maintaining the superior Si-SiO 2 interface. The perhaps most commonly used combination is that with Si 3 N 4 , 2,3 but other materials, e.g., Ta 2 O 5 , 4,5 have been suggested. Another issue in gate-stack scaling is the problem with depletion of the polysilicon reducing the effective capacitance. 6 A replacement for the polysilicon will therefore probably be needed. 1 This may force the use of different gate materials for PMOS and NMOS transistors to realize satisfactory threshold voltages. For NMOS transistors, aluminum is a suitable candidate with its Fermi level close to the conduction band in the silicon. In this study the focus is on MOS structures where the gate material is aluminum. We report on a way to increase the gate-tochannel capacitance without increasing the leakage current which is possible in this particular device structure.Experimental Devices.-The devices used in this study were based on <100> oriented, 1-10 ⍀ cm substrates of n-and p-type silicon. The wafers were oxidized to form a thick field oxide followed by a lithography step where the devices with areas ranging from 2 ϫ 2 m to 100 ϫ 100 m were defined. The gate dielectric was then formed using one of the methods described below, immediately after which aluminum was evaporated from a resistively heated crucible to form the top contacts of the metal oxide semiconductor (MOS) structures. For comparison, polysilicon (POCl 3 -doped) or chromium was used as the gate material on a few devices. Finally aluminum was evaporated onto the back of the wafers.Four types of ultrathin gate dielectrics were studied, as summarized in Table I: (i) thermally grown in a 2% O 2 in N 2 mixture at 900ЊC for 20 min (denoted HTn/p); (ii) thermally grown at 750ЊC for 10 min in a pure O 2 environment (denoted LTn), (iii) deposited at 300ЊC using remote plasma-enhanced chemical vapor deposition (denoted RPECVD), and (iv) oxidized at 300ЊC using a remote oxygen plasma (denoted RPEO). For comparison, thicker oxides were grown on p-type substrates in pure oxygen at 850ЊC to a final thickness ranging from 92 to 175 Å (d...

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supporting

confidence: 75%

Electrical Characterization of Interfacial Reactions in Ultrathin Oxides during Postmetalization Anneal

Ragnarsson

Aderstedt

Lundgren

1999

J. Electrochem. Soc.

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“…24 To check if the acquired spectra correspond to that of a gold silicide, we have calculated the electronic structure of such compounds by using the formalism of the densityfunctional theory, 25 with the help of the WIEN2K package. 26 Since the atomic structure of gold silicides is not well known, the calculations have been performed with the atomic structures of nickel silicide compounds.…”

Section: B Comparison With Electronic Structure Calculationsmentioning

confidence: 99%

X-ray spectroscopy study of electronic structure of laser-irradiated Au nanoparticles in a silica film

Jonnard

Bercegol

Lamaignère

et al. 2005

Journal of Applied Physics

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The electronic structure of gold nanoparticles embedded in a silica film is studied, both before and after irradiation at 355 nm by a laser. The Au 5d occupied valence states are observed by x-ray emission spectroscopy. They show that before irradiation the gold atoms are in metallic states within the nanoparticles. After irradiation with a fluence of 0.5 J/cm2, it is found that gold valence states are close to those of a metal-poor gold silicide; thanks to a comparison of the experimental Au 5d states with the calculated ones for gold silicides using the density-functional theory. The formation of such a compound is driven by the diffusion of the gold atoms into the silica film upon the laser irradiation. At higher fluence, 1 J/cm2, we find a higher percentage of metallic gold that could be attributed to annealing in the silica matrix

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“…Other authors (6) suggest the formation of Au-Si bonds, possible even at room temperature. Gold bonds to Si atom of SiO2 and reduces SiO2 to an intermediate oxidation state at the interface.…”

Section: The Causes Of Adhesionmentioning

confidence: 99%

An investigation of gold/ceramic and gold/glass interfaces

2002

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Abstract:This paper describes how various characterisation methods can be used to investigate the physicochemical and spectral properties of gold films in contact with glass or ceramic. The interface between the metal and substrate has been given special attention. The examples chosen to illustrate this include: liquid gold films (decorated and fired) or inlayed gold layers on ceramic wares and "sandwich" gold foils between two glass sheets for mosaic application. Characterisation methods include: microanalytical scanning electron microscopy, X-ray diffraction, ion beam analyses (PIXE: particle induced X-ray emission; RBS: Rutherford back-scattering spectrometry), photo-spectrometry and colorimetry. The adhesion mechanism and colour behaviour of the coated objects is discussed.Gold films coated on, or in contact with, oxides (glass or ceramic) have a great number of artistic and technological applications. Gold has been used to decorate ceramic and glass for centuries, e.g. mosaic art and more recently gold films are used in high technology areas to modify surface properties. In most applications, the colour is of great importance, and also the strength and durability of the films. The nature of the adhesion at the interface between coating and substrate is vital in terms of durability. Information about the adhesion mechanism may be obtained by a physicochemical investigation at high resolution.

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Au and Al interface reactions with SiO2

Cited by 85 publications

References 27 publications

Electrical Characterization of Interfacial Reactions in Ultrathin Oxides during Postmetalization Anneal

Electrical Characterization of Interfacial Reactions in Ultrathin Oxides during Postmetalization Anneal

X-ray spectroscopy study of electronic structure of laser-irradiated Au nanoparticles in a silica film

An investigation of gold/ceramic and gold/glass interfaces

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