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Amorphous SiO2 (a-SiO2) layers were prepared using a thermal oxidation method. The SiO2 layers were nitrided at a temperature Tn between 450 and 650 °C utilizing a plasma generation system, in which the layers before the nitridation were simultaneously grown on two different n-type crystalline Si substrates, one having a high resistivity for electron-spin resonance (ESR) and Fourier transform infrared absorption measurements and another having a low resistivity for current–voltage (I–V) measurement. We found the breakdown strength, estimated based on the I–V characteristics, increased with increasing Tn until 550 °C, but the annealing at a further high Tn caused also a decrease in the breakdown strength. We found a strong correlation between the changes in the I–V characteristics and those in the bonding properties, and this correlation was also discussed in connection with the change in the ESR properties for the a-SiOxNy layers. Furthermore, incorporation of N atoms into SiO2 layers at Tn=550 °C was suggested to improve the structural properties and the electrical properties. [ABSTRACT FROM AUTHOR]

Abstract: We exposed crystalline Si (C-Si) substrates to a NH3 plasma by the method of plasma enhanced chemical vapor deposition (PECVD) and the Si substrates were nitrided at a nitridation temperature, T n, between 300 and 600°C. The nitrided layers were grown directly on n-type C-Si substrates with high resistivity for measurements of electron resonance (ESR) and Fourier transform infrared (FTIR) absorption. The intensity of the N–H IR bending band increased with increasing T n up to 450°C, and then decreased again with a further increasing in T n. We found a strong correlation between the change in the ESR spin density, N s, and that in the N–H bending intensity, which was obtained from the spectral intensity at around 1200cm−1. Furthermore, incorporation of N atoms in amorphous Si x N y layers may improve the structural property at T n =450°C for various insulating applications. In addition, we found that the atomic densities and/or composition of a-Si x N y may decrease the BHF etch rate. [Copyright &y& Elsevier]

Amorphous SiNx:H films were prepared by rf glow discharge (GD) of SiH4-N2-H2 mixtures at 300 °C using a new decomposition technique. The optical gap Eg increases slowly with the ratio N2/SiH4 up to a critical gap Egc of 2.5–3.0 eV, and then rapidly increases up to 5.3 eV. The spin density Ns from electron spin resonance of Si dangling bonds increases with N2/SiH4 until Eg reaches Egc. Above Egc, Ns rapidly decreases in contrast with that of conventional GD films, but in similarity to pyrolytic films. The slope B in Tauc equation for optical absorption corresponds well with Ns. [ABSTRACT FROM AUTHOR]

Abstract: The structural properties of polycrystalline silicon films, prepared by plasma enhanced chemical vapor deposition system, with different flow rates of SiH4/SiF4 mixtures at 300°C were investigated. This study indicates that the low hydrogen coverage on the growing surface, under optimum fluorine radicals, will be leaded to an improvement of crystallized area as compared with case of high hydrogen coverage surface. Moreover, the studies of the role of SiH4 and SiF4 radicals show that the SiH4 radicals are important in the nucleation and growth of grains. However, SiF4 radicals are effective in the structural change of grain boundaries regions and by this way, in the present system, establish the growth of grains under the dominant 〈110〉 direction. The stress investigation indicates that addition of high flow rate of SiF4 in amorphous film, results in the nearly stress free films. Finally, we found that the changes in g-value reflect the changes in the intrinsic compressive and tensile stress in the both polycrystalline and amorphous silicon films. [Copyright &y& Elsevier]

Amorphous silicon oxynitride, a-SiOxNy, layers were prepared by nitridation of 7-nm thick thermally grown silicon dioxide, a-SiO2, layers on n-type crystalline Si substrates, in NH3 plasma with different temperatures (TP=300–500 °C). The compositional and structural properties for the a-SiOxNy layers were examined using current–voltage (I–V), capacitance–voltage (C–V), electron spin resonance (ESR), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy and Fourier transform infrared measurements. We found a strong correlation between the change in the ESR spin density and that in the C–V characteristics with varying TP. These results were interpreted as indicating a change in the compressive strain. The I–V characteristics showed that the breakdown strength monotonically decreased with increasing TP. In the distribution of the constituent atoms, the AES profiles were roughly independent of TP. The changes in the 800 and 1070 cm−1 IR absorption bands were also examined based on those in the compressive strain, as well as a proposal for interpreting the ESR and C–V results. [Copyright &y& Elsevier]

Amorphous Si oxynitride (a-SiOxNy) films were deposited at 300 °C using a plasma-enhanced chemical vapor deposition technique, by varying the NH3 flow rate, [NH3], under fixed SiH4 and O2 flow rates to control the x- and y-values. The characteristics of defects were investigated vis-a`-vis structural and bonding properties. These films were ‘stoichiometric’, including no or less homobonds. As [NH3] increases, the x- and y-values decreased and increased, respectively, and a relationship of 2x+3y=4.14 (±0.02) was found. With increasing [NH3], the deposition rate increased, but the defect density and the stress can be decreased. [Copyright &y& Elsevier]