Silicon oxynitride

Silicon-containing ceramics include the oxide materials, silica and the silicates the binary compounds of silicon with non-metals, principally silicon carbide and silicon nitride silicon oxynitride and the sialons main group and transition metal silicides, and, finally, elemental silicon itself. There is a vigorous research activity throughout the world on the preparation of all of these classes of solid silicon compounds by the newer preparative techniques. In this report, we will focus on silicon carbide and silicon nitride. 

The other platform is dielectrics, for example, silicon dioxide, silicon nitride, silicon oxynitride, tantalum pentoxide, and titanium dioxide. They can be deposited by various methods, such as plasma-enhanced chemical vapor deposition, thermal evaporation, electron-beam evaporation, and sputtering. There are a number of dielectrics with refractive indices ranging from 1.45 to 2.4, facilitating diverse waveguide designs to satisfy different specification. Dielectrics have two other... 

Table 10.1 summarizes the parameters of the final four-channel YI structure. The IO chips are fabricated using Silicon-oxynitride (cleanroom) technology. Details of the fabrication process have been described extensively elsewhere41. 

Silicon oxynitride, 22 541 Silicon peroxides, 18 439 Silicon photoconductors, doped,... 

S. Asti, A.M. Gu, E. Scheid, and J.P. Guidemt. Design of a low power SnOa gas sensor integrated on silicon oxynitride membrane Sensors and Actuators B67 (2000), 84-88. 

The most common examples of high index contrast waveguides are silicon-on-insulator (SOI) waveguides, and silicon oxynitride... 

Melloni, A., Costa, R., Monguzzi, P., and Martinelli, M., 2003, Ring-resonator filters in silicon oxynitride technology for dense wavelength-division multiplexing systems. Opt. Leu. 28(17) 1567-1569. 

Amongst other systems reported for the Knoevenagel condensation reaction have been, nitrogen incorporated ZSM-5 and high surface area silicon oxynitride." The ZSM-5 based -system potentially combines tuneable acid/ base properties with shape selectivity leading to the potential of selective conversion and/or unusual reaction pathways. 

Dielectric Deposition Systems. The most common techniques used for dielectric deposition include chemical vapor deposition (CVD), sputtering, and spin-on films. In a CVD system thermal or plasma energy is used to decompose source molecules on the semiconductor surface (189). In plasma-enhanced CVD (PECVD), typical source gases include silane, SiH4, and nitrous oxide, N20, for deposition of silicon nitride. The most common CVD films used are silicon dioxide, silicon nitride, and silicon oxynitrides. 

Addition of nitric oxide, NO, to the plasma during Si02 deposition gives silicon oxynitride films. 

Materials made of silicon nitride, silicon oxynitride, or sialon-bonded silicon carbide have high thermal shock and corrosion resistance and may be used for pump parts, acid spray nozzles, and in aluminum reduction cells (156—159). A very porous silicon carbide foam has been considered for surface combustion burner plates and filter media. It can also be used as a substrate carrying materials such as boron nitride as planar diffusion source for... 

This model goes a long way towards explaining most experimental results reported in the literature for ISFETs with oxide or nitride surfaces. Unfortunately, the properties of these materials prepared in different laboratories are very different. It is known that silicon nitride (really silicon oxynitride SisNztOx) forms an oxygen-rich layer at the surface, whose thickness depends on the deposition conditions. This passivation layer forms rapidly (in a matter of hours) and is very stable, even under continuous exposure to aqueous electrolyte. The hydration of this layer seems to fit the requirements and predicted behavior of the Sandifer model. Consequently, ISFETs that have been exposed to aqueous solution for more than one hour show no adsorption effects which would be expected from the SBT model. 

The hydration layer model more or less fits the behavior of all oxides and of silicon oxynitride. The latter has a great advantage over other pH-sensitive layers because it is an excellent passivation material itself that can be prepared virtually pinhole-free. On the other hand, even thermally grown Si02 has pinholes and cracks that form a leakage path. It is that leakage path that apparently served as a... 

O-SiAlON is another crystalline phase of interest. There is a limited solubility of alumina in silicon oxynitride structure to give O-SiAlONs, represented by the formula Si2 A-Aly01+A.N2 where ovaries from zero to 0.2. Formation of O-SiAION occurs in the same mechanism as P-SiAlON i.e. Si + N is replaced by Al + O. The lattice parameters of O-SiAION, Si2 AI/)i+aN2 a, increase in a very typical way with the x value.37... 

Finally, we will consider PECVD silicon oxynitrides, and their unique characteristics. When oxygen is added to a PECVD nitride film, there are indications that it may improve its crack resistance as a final passivation layer.13 Also, there may be advantages in terms of its electrical characteristics as an interlayer dielectric. Therefore, the nature of films grown when N20 is added to a SiH4, NH3 and He gas mixture in a high frequency (13.56 MHz), cold-wall, parallel-plate reactor have been studied. 

Nitridated silica surfaces are very important in the semi-conductor and microelectronic industries. However, direct ammoniation of silica is -so far- a very uncontrollable procedure the required reaction temperatures are very high (> 1500 K), a lot of side products are formed (typically Si2N20, silicon-oxynitride) and the nitride diffuses into the silica matrix. Direct nitridation of silica should therefore be considered as a bulk synthesis, and not as a surface modification technique. 

Several recent studies7,9,10,23,26 have reported attempts to create silicon nitride by direct ammoniation of silica, usually as a spin-off of the integrated circuit technology research. Most of these studies agree that at temperatures about 1473 K up to 20 -25 % (w/w) nitrogen can be incorporated, but silicon nitride is seldom formed. The final product of this direct nitridation method is silicon-oxynitride (Si2N20) with residual silica. The nitridation is not restricted to the surface, but the N diffuses also into the bulk structure of the silica. No adequate mechanisms were presented to explain the observed reactions. 

Koster, T.P.M., Spee, C.I.M.A., De Kreuk, C.W. and Mackor, A. 1987. The stabilization of silicon photoelectrodes by a silicon oxynitride coating. Extended abstracts, 38th Meeting International Society of Electro-chemistry, Maastricht, September 13-18,1987. Vol. II, Abstr. 6.73. Pp.659-661. 

Brosset, C., and I. Idrestedt Crystal Structure of Silicon Oxynitride, Si2N20. Nature 201,1211 (1964). Structure of Si2NsO. Acta chem. scand. 18, 1879-1886 (1964). 

Gundiah. G.. Madhav. G. V. Govindaraj. A. Rao, C. N. R. Synthesis and characterization of silicon carbide, silicon oxynitride and silicon nitride nanowires. J. Mater. Chem. 2002 12. 1606-1611. 

Germann R, Salemink HWM, Beyeler R, Bona GL, Horst F, Massaiek I, Of ein BJ (2000) Silicon oxynitride layers for optical waveguide applications. J Electrochem Soc 147 2237-2241... 

Wdrhoff K, Lambeck PV, Driessen A (1999) Design, tolerance analysis, and fabrication of silicon oxynitride based planar optical waveguides for communication devices. J Lightwave Technol 17 1401-1407... 

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