AVS 52nd International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeA

Paper TF-WeA5
Sputter Deposition of Silicon Oxynitride for Waveguide Applications

Wednesday, November 2, 2005, 3:20 pm, Room 306

Session: Fundamentals of Thin Films
Presenter: J.G. Sandland, Massachusetts Institute of Technology
Authors: J.G. Sandland, Massachusetts Institute of Technology
A. Eshed, Massachusetts Institute of Technology
L.C. Kimerling, Massachusetts Institute of Technology
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Silicon oxynitride (SiON) is an ideal waveguide material because the SiON materials system provides substantial flexibility in composition and refractive index. SiON can be varied in index from that of silicon dioxide (n=1.46) to that of silicon-rich silicon nitride (n~2.3). This flexibility in refractive index allows for the optimization of device performance by allowing trade-offs between the advantages of low-index contrast systems and the benefits of high-index-contrast systems. We present sputter processing as an alternative to traditional CVD processing of SiON. We explore a co-sputtered deposition from a silicon oxide and a silicon nitride target, and reactive sputtering process from a silicon nitride target in oxygen ambient. Silicon nitride sputtered from a silicon nitride target is also investigated. Models were developed predicting the index and composition as function of deposition conditions. A materials study is provided that shows sputtered SiON to be a homogeneous material that gives good control of refractive index. Reactively sputtered SiON is shown to be Si-rich. These sputtered materials investigated for use as a core material in optical waveguides. Low loss waveguides are demonstrated for both co-sputtered and reactively sputtered depositions. Losses below 1 dB/cm are shown for co-sputtered deposition (n=1.65). These waveguide losses are then related back to our sputtering model, and silicon dangling bonds are shown to contribute to the losses in the waveguides.