Wear and Nanomechanical Studies of Silicon Oxide and Silicon Nitride Thin Films for MEMS Applications

Thin films of amorphous silicon oxide and silicon nitride are routinely used as gate dielectrics in silicon-based microelectronic devices. It is valuable to be able to image them and measure their thicknesses quickly and accurately. This brief note describes conditions that can be used to obtain accurate and reproducible TEM images of oxide-nitride-oxide (ONO) thin films.Obtaining adequate contrast differences between oxide and nitride is not trivial because they have the same average atomic number, and both phases are amorphous. As stoichiometric compounds, both SiO2 and Si3N4 would have average atomic numbers equal to 10. For SiO2, (14+2(8))/3=10, and for Si3N4, (3(14)+4(7))/7=10. Thus, the atomic number contrast between these two is weak or nonexistent. Similarly, the amorphous character prevents the use of conventional diffraction contrast techniques.However, the density of Si3N4 (3.2 g/cm3) is considerably greater than the density of SiO2 (2.6 g/cm3), reflecting the higher average coordination of N compared with O.

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Reliability of MEMS Materials: Mechanical Characterization of Thin-Films using the Wafer Scale Bulge Test and Improved Microtensile Techniques

MRS Proceedings ◽

10.1557/proc-1052-dd01-02 ◽

2007 ◽

Vol 1052 ◽

Cited By ~ 5

Author(s):

Joao Gaspar ◽

Marek Schmidt ◽

Jochen Held ◽

Oliver Paul

Keyword(s):

Thin Films ◽

Silicon Nitride ◽

Polycrystalline Silicon ◽

Weibull Modulus ◽

Silicon Oxide ◽

Mechanical Characterization ◽

Bulge Test ◽

Material Parameters ◽

Statistical Relevance

AbstractThis paper reports on recent improvements of the bulge and microtensile techniques for the reliable extraction of material parameters such as the Young's modulus E, Poisson's ratio ν, plane strain modulus Eps = E/(1–ν2), prestress σ0, fracture strength μ, Weibull modulus m and strain hardening coefficients n, and on the direct comparison between the two methods. The bulge technique is extended to full wafer measurements enabling throughputs of data with statistical relevance whereas key improvements of a previous fabrication process of microtensile specimens lead now to much higher yields, approaching 100%. Both techniques are applied to an extensive set of materials, brittle and ductile, typically used in MEMS applications. These include thin films of silicon nitride, silicon oxide, polycrystalline silicon and aluminum deposited by techniques such as thermal oxidation, LPCVD, PECVD and PVD.

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Atomic scale simulation of physical sputtering of silicon oxide and silicon nitride thin films

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2005.09.045 ◽

2006 ◽

Vol 286 (1) ◽

pp. 71-77 ◽

Cited By ~ 23

Author(s):

Dong-Ho Kim ◽

Gun-Hwan Lee ◽

Seung Yup Lee ◽

Do Hyun Kim

Keyword(s):

Thin Films ◽

Silicon Nitride ◽

Silicon Oxide ◽

Atomic Scale ◽

Physical Sputtering

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Metalorganic chemical vapor deposition of aluminum oxide on silicon nitride

MRS Proceedings ◽

10.1557/proc-751-z3.45 ◽

2002 ◽

Vol 751 ◽

Author(s):

Anindya Dasgupta ◽

Abhijit Roy Chowdhuri ◽

Christos G. Takoudis

Keyword(s):

Thin Films ◽

Silicon Nitride ◽

Aluminum Oxide ◽

Silicon Oxide ◽

Chemical Vapor ◽

Aluminum Silicate ◽

Excess Oxygen ◽

Silicon Substrates ◽

Interfacial Layers ◽

Film Substrate

ABSTRACTThin films of aluminum oxide were deposited on silicon nitride thin films using trimethylaluminum and oxygen at 0.5 Torr and 300 °C. Fourier transform infrared (FTIR) and x-ray photoelectron spectroscopic (XPS) analyses of these films showed no aluminum silicate phase at the film-substrate interface. The O/Al ratio in the deposited film was found to be higher than that in stoichiometric Al2O3 indicating the presence of excess oxygen. FTIR spectroscopy and XPS of the annealed samples did not show any formation of silicon oxide, oxynitride or silicate at the aluminum oxide/silicon nitride interface. In contrast to aluminum oxide on clean silicon substrates, using ultrathin silicon nitride as a barrier layer could prevent excess oxygen migration towards the Si substrate and formation of any interfacial layers.

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X-ray reflectivity studies of very thin films of silicon oxide and silicon oxide–silicon nitride stacked structures

Journal of Non-Crystalline Solids ◽

10.1016/s0022-3093(00)00380-x ◽

2001 ◽

Vol 280 (1-3) ◽

pp. 228-234 ◽

Cited By ~ 4

Author(s):

S. Santucci ◽

A.V. la Cecilia ◽

A. DiGiacomo ◽

R.A. Phani ◽

L. Lozzi

Keyword(s):

Thin Films ◽

Silicon Nitride ◽

Silicon Oxide ◽

X Ray

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Study of the properties of thin films of silicon nitride and silicon oxide using effective medium theories

Journal of Vacuum Science & Technology A Vacuum Surfaces and Films ◽

10.1116/1.1486005 ◽

2002 ◽

Vol 20 (4) ◽

pp. 1369-1373 ◽

Cited By ~ 4

Author(s):

Redhouane Henda

Keyword(s):

Thin Films ◽

Silicon Nitride ◽

Silicon Oxide ◽

Effective Medium ◽

Effective Medium Theories

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Fracture Properties of LPCVD Silicon Nitride and Thermally Grown Silicon Oxide Thin Films From the Load-Deflection of Long $\hbox{Si}_{3}\hbox{N}_{4}$ and $\hbox{SiO}_{2}/\hbox{Si}_{3}\hbox{N}_{4}$ Diaphragms

Journal of Microelectromechanical Systems ◽

10.1109/jmems.2008.928706 ◽

2008 ◽

Vol 17 (5) ◽

pp. 1120-1134 ◽

Cited By ~ 22

Author(s):

Jinling Yang ◽

J. Gaspar ◽

O. Paul

Keyword(s):

Thin Films ◽

Silicon Nitride ◽

Silicon Oxide ◽

Oxide Thin Films ◽

Fracture Properties ◽

Thermally Grown

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Extraction of the Coefficient of Thermal Expansion of Thin Films from Buckled Membranes

MRS Proceedings ◽

10.1557/proc-546-103 ◽

1998 ◽

Vol 546 ◽

Cited By ~ 7

Author(s):

V. Ziebartl ◽

O. Paul ◽

H. Baltes

Keyword(s):

Thin Films ◽

Finite Element ◽

Thermal Expansion ◽

Silicon Nitride ◽

Excellent Agreement ◽

Energy Minimization ◽

Coefficient Of Thermal Expansion ◽

Temperature Dependent ◽

Minimization Method ◽

Energy Minimization Method

AbstractWe report a new method to measure the temperature-dependent coefficient of thermal expansion α(T) of thin films. The method exploits the temperature dependent buckling of clamped square plates. This buckling was investigated numerically using an energy minimization method and finite element simulations. Both approaches show excellent agreement even far away from simple critical buckling. The numerical results were used to extract Cα(T) = α0+α1(T−T0 ) of PECVD silicon nitride between 20° and 140°C with α0 = (1.803±0.006)×10−6°C−1, α1 = (7.5±0.5)×10−9 °C−2, and T0 = 25°C.

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