AVS 47th International Symposium
    Flat Panel Displays Monday Sessions
       Session FP-MoA

Paper FP-MoA9
Deposition of Silicon Nitride on a Polymer Substrate by Plasma Enhanced Chemical Vapor Deposition

Monday, October 2, 2000, 4:40 pm, Room 313

Session: Flexible Displays
Presenter: D. Guerin, University of Delaware
Authors: D. Guerin, University of Delaware
S.I. Shah, University of Delaware
Correspondent: Click to Email
Silicon nitride thin films were deposited on poly(ethyleneterephthalate) (PET) by plasma-enhanced chemical-vapor deposition (PECVD) in a capacitively coupled reactor. The process of film growth was examined using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Films were grown for varying lengths of time and transferred under vacuum into an attached XPS system. AFM measurements were performed ex situ. Results indicated that the film growth process was highly dependent on the power density of the plasma. The higher the power density, the longer it took to achieve a pure silicon nitride film. With higher power plasma, the etching of the polymer substrate was observed in the initial stages of the process. This provided carbon and oxygen atoms which get incorporated into the film. Power density also affects the morphology of the thin films. In lower energy plasmas, there is less chemical interaction between the substrate and deposited film. High resolution XPS measurements of the C 1s region indicated that the main effect of the plasma on the substrate was to modify the surface such that an amorphous polymer interface was created between the bi-axial crystalline polymer and the amorphous inorganic film. The little carbon that did get incorporated into the film was C-H bound. Above some critical power density a distinct carbon peak appeared indicating that carbon from the substrate is being incorporated into the film through either Si-C or N-C bonds. AFM measurements revealed that higher energy deposition led to higher nucleation density and surface coverage. XPS measurements, however, continued to show the C 1s peak even after 40 sec. of deposition. In samples deposited at low energy, the C 1s peak disappeared after only 30 sec. of deposition. Based on these observations, we will present a model of the initial stages of silicon nitride growth on PET.