Journal ArticleDOI
The Etching of Silicon Nitride in Phosphoric Acid with Silicon Dioxide as a Mask
W. van Gelder,V.E. Hauser +1 more
TLDR
In this article, the etch rate of silicon nitride, silicon dioxide, and silicon in refluxed boiling phosphoric acid was measured as a function of temperature (and concentration) in the range of 140°-200°C.Abstract:
The water content of phosphoric acid in etching silicon nitride and silicon dioxide plays an important role. An increase in water content increases the etch rate of silicon nitride and decreases the etch rate of silicon dioxide. The highest possible temperature for a fixed water content at atmospheric pressure in the system is realized by boiling the liquid and refluxing the vapor phase. Refluxed boiling phosphoric acid at 180°C was found to be a useful etchant for silicon nitride films. The etch rate is 100 Aa/min. Under the same conditions deposited silicon dioxide had an etch rate of 0–25 Aa/min depending on the method of preparation, and elemental silicon 3 Aa/min. Etch rates of silicon nitride, silicon dioxide, and silicon in refluxed boiling phosphoric acid were measured as a function of temperature (and concentration) in the range of 140°–200°C. All etch rates increased with temperature. The "apparent" activation energies are 12.7, 27.6, and 26.4 kcal/mole, respectively. The etch rate of silicon nitride in phosphoric acid of constant concentration was measured as a function of temperature only. In this case the "real" activation energy was 22.8 kcal/mole. The difference in etch rate between silicon nitride, deposited silicon dioxide, and silicon offers a technique for etching contact holes in silicon nitride using deposited silicon dioxide as a mask. Such a technique was used successfully in making transistors with silicon nitride over as a junction seal.read more
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Journal ArticleDOI
Etch rates for micromachining processing
TL;DR: The etch rates for 317 combinations of 16 materials (single-crystal silicon, doped, and undoped polysilicon, several types of silicon dioxide, stoichiometric and silicon-rich silicon nitride, aluminum, tungsten, titanium, Ti/W alloy, and two brands of positive photoresist) used in the fabrication of microelectromechanical systems and integrated circuits in 28 wet, plasma, and plasmaless-gas-phase etches (several HF solutions, H/sub 3/PO/sub 4), HNO/sub
Journal ArticleDOI
Versatile ultrathin nanoporous silicon nitride membranes
TL;DR: Compared with typical membranes with cylindrical pores, the conical and double-conical pores reported here allow for higher fluxes, a critical advantage in separation applications, and gives advantages for single biomolecule detection applications such as nanopore-based DNA analysis.
Journal ArticleDOI
Optimization of a low-stress silicon nitride process for surface-micromachining applications
TL;DR: A detailed examination of the effects of deposition parameters, using LPCVD, and subsequent processing on the characteristics of silicon nitride is presented in this paper, where the properties investigated are deposition rate, refractive index, etch rate and intrinsic strain.
Journal ArticleDOI
The preparation, characterization and applications of silicon nitride thin films
Journal ArticleDOI
Stability of oriented silicalite-1 films in view of zeolite membrane preparation
M.J. den Exter,H. van Bekkum,C.J.M. Rijn,Freek Kapteijn,Jacob A. Moulijn,H. Schellevis,C.I.N. Beenakker +6 more
TL;DR: In this article, b-and (a, b)-oriented monolayers on silicon wafers were grown as b- and b-oriented mono-layer on silicon and silicon nitride windows, aiming at two new membrane systems.
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