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Silicon nanocrystallites embedded in silicon nitride were prepared by high-temperature annealing of silicon-rich silicon nitride (SRN) via the phase separation reaction. The silicon rich nitride films were deposited by low-pressure chemical-vapor deposition (LPCVD) and high temperature annealing. At sufficiently high temperatures, nanocrystallites are formed as a result of phase separation effect. The chemical composition and bonding structure of the silicon oxide and nitride based nanocrystals were analyzed using X-ray photoelectron spectroscopy (XPS). Photoluminescence (PL) measurements were also conducted to probe the luminescent properties of the SRN films. © 2008 IEEE.

Silicon nanocrystallites embedded in silicon nitride were prepared by high-temperature annealing of silicon-rich silicon nitride (SRN) via the phase separation reaction. Chemical composition and bonding structures of the SRN were explored using X-ray photoelectron spectroscopy (XPS). Raman spectroscopy and photoluminescence (PL) measurements were also conducted to probe the luminescent properties of the SRN films. We found that the intensities and the energy locations of the SRN films depend strongly on both the deposition and annealing conditions. High-temperature (∼900°C) annealing of as-deposited SRN gives rise to a strong PL because of the formation of denser crystalline Si phases as a result of phase separation of the SRN films. © 2007 IEEE.

Thick oxynitride films were prepared by plasma enhanced chemical vapor deposition (PECVD) with N2O, NH3 and SiH4 precursors. The composition and the bonding structure of the oxynitride films were investigated with Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS). Results showed that the silicon oxynitride deposited with gas flow rates of NH4/N2O/SiH4 = 10/400/10 (sccm) has favorable properties for integrated waveguide applications. The refractive index of this layer is about 1.5 and the layer has comparative low densities of O-H and N-H bonds. The O-H bonds can be readily eliminated with high temperature annealing of the as-deposited film in nitrogen ambient. Annealing at temperature of 1000 °C or above which can significantly suppress both the N-H bonds and O-H bonds is preferred. Simple ridge type waveguide with cross-section of 3 μm×2.5 μm for the core layer (n = 1.57) was fabricated. This waveguide is able to transmit signal in either TE or TM mode and the number of mode is eight and the bending radius of the waveguide can be reduced to about 6 μm. © 2006 IEEE.

This work reports a method for reducing hydrogen content in silicon oxynitride film for integrated optical applications. The silicon oxynitride (SiON) films were grown by plasma enhanced chemical vapor deposition (PECVD) with N2O, NH3 and SiH4 as precursor gases. Using higher flow rate of SiH4 and NH3, Si-rich oxynitride films with high refractive index were obtained. Detailed ellipsometry and Fourier transform infrared (FTIR) spectroscopy characterization of the as-deposited samples and samples with thermal oxidation/annealing were conducted. Results showed that the silicon oxynitride deposited with gas flow rates of NH3/N2O/SiH4=20/500/20 (seem) has favorable properties for integrated waveguide applications. The refractive index of this layer is about 1.57 at 632.8 nm wavelength and the layer has a comparative low density of N-H bonds. With a high temperature annealing treatment in oxygen ambient, the hydrogen content in the as-deposited SiON film was reduced by 87% as results of excess silicon oxidation and hydrogen bond removal. © 2005 IEEE.

This work explores the technology for preparing low hydrogen-content silicon oxynitride film for integrated optical waveguide applications. Plasma-enhanced chemical vapor deposition with N2O, NH3 and SiH4 precursors was used for the oxynitride preparation. The flow rates of the precursor gases are varied to study processing effects on the refractive index and the content of hydrogen bonds. The refractive index of the oxynitride film can be readily tuned between 1.47 and 1.92 by varying the gas flow rates. The composition and the bonding structure of the oxynitride films were investigated with Fourier transform infrared (FTIR) spectroscopy. Results showed that the silicon oxynitride deposited with gas flow rates of NH4/N2O/SiH4 = 10/400/10 (sccm) has favorable properties for integrated waveguide applications. The refractive index of this layer is about 1.5 and the layer has a comparative low density of N-H bonds. The high content of O-H bond can be readily eliminated with high-temperature annealing of the as-deposited film in nitrogen ambient. Annealing at temperature of 1000 degrees C or above which can significantly suppress both the N-H bonds and O-H bonds is preferred. Waveguide devices built with oxynitride prepared at those conditions would have properties of low propagation loss and small size. (c) 2005 Published by Elsevier B.V.