Composition and Thickness of RE Sputtered Amorphous Silicon Alloy Films

Because the composition and the thickness of the thin films are very important forthe fabrication of the devices, in this study we have undertaken the determination of thecomposition and the thickness of the RF sputtered amorphous silicon alloy thin filmsdeposited at room temperature under very different preparation conditions by usingvarious techniques. Incorporation of argon is demonstrated in the room temperaturedeposited films and the thickness of the films measured by different methods such asRutherford backscattering, spectroscopicellipsometry and step-profiler are found to be inreasonable agreement with each other

Structural and electrical properties of nanostructured silicon carbon films

Abstract The effect of the rf power on the structural and electrical properties of nanostructured silicon carbon films deposited by Plasma Enhanced Chemical Vapour Deposition system, using silane and methane gas mixture highly diluted in hydrogen, has been investigated. The structural and electrical properties are found to depend strongly on rf power. The increase of the rf power decreases the size of the silicon crystallites as well as the crystalline fraction and increases the carbon content in the films. The study not only indicates the correlation between crystalline fraction and the electrical conductivity but also reveals the presence of nanocrystallites in the films deposited at high rf power

Valence electronic structure of Mn in undoped and doped lanthanum manganites from relative K x-ray intensity studies

Relative $K$ x-ray intensities of $Mn$ in $Mn$, $MnO_{2}$, $LaMnO_{3}$ and $La_{0.7}B_{0.3}MnO_{3}$ ($B$ = $Ca$, $Sr$, and $Ce$) systems have been measured following excitation by 59.54 keV $\gamma$-rays from a 200 mCi $^{241}$Am point-source. The measured results for the compounds deviate significantly from the results of pure $Mn$. Comparison of the experimental data with the multiconfiguration Dirac-Fock (MCDF) effective atomic model calculations indicates reasonable agreement with the predictions of ionic model for the doped {manganites except} that the electron doped $La_{0.7}Ce_{0.3}MnO_{3}$ and hole doped $La_{0.7}Ca_{0.3}MnO_{3}$ compounds show some small deviations. The results of $MnO_{2}$ and $LaMnO_{3}$ deviate considerably from the predictions of the ionic model. Our measured $K\beta/K\alpha$ ratio of $Mn$ in $La_{0.7}Ca_{0.3}MnO_{3}$ cannot be explained as a linear superposition of $K\beta/K\alpha$ ratios of $Mn$ for the end members which is in contrast to the recent proposal by Tyson et al. from their $Mn$ $K\beta$ spectra.Comment: 14 pages, 4 figures. to appear in NIM-B.Please send an e-mail for figure

Nanostructured silicon carbon thin films grown by plasma enhanced chemical vapour deposition technique

Nanostructured silicon carbon thin films, composed of Si nanocrystallites embedded in hydrogenated amorphous silicon carbon matrix, have been prepared by varying rf power in ultra high vacuum plasma enhanced chemical vapour deposition system using silane and methane gas mixtures diluted in hydrogen. In this paper we have studied the compositional, structural and electrical properties of these films as a function of rf power. It is shown that with increasing rf power the atomic densities of carbon and hydrogen increase while the atomic density of silicon decreases, resulting in a reduction in the mass density. Further, it is demonstrated that carbon is incorporated into amorphous matrix and it is mainly bonded to silicon. The study has also revealed that the crystalline volume fraction decreases with increase in rf power and that the films deposited with low rf power have a size distribution of large and small crystallites while the films deposited with relatively high power have only small crystallites. Finally, the enhanced transport properties of the nanostructured silicon carbon films, as compared to amorphous counterpart,have been attributed to the presence of Si nanocrystallites

Influence of rf power on the properties of nanostructured silicon-carbon films deposited by PECVD

Nanostructured films composed of silicon crystallites embedded in an hydrogenated amorphous silicon carbon matrix have been deposited by plasma enhanced chemical vapour deposition from silane methane mixture diluted in hydrogen varying the rf power from 30 to 80 W. The films have been investigated in their structural, optical and electrical properties. The increase of rf power appears to be an effective deposition parameter to increase the incorporation of carbon in the amorphous matrix and to facilitate the reduction of the crystallite size. The dark conductivity of the studied films decreases from 1.4 × 10-3 to 3.5 × 10-9 Ω-1cm-1 while the photo conductivity decreases from to 3.2 × 10-3 to 3.5 × 10-7 Ω-1cm-1 as a function of rf power. The photosensitivity is about 100 in 40-80 W rang