Spatial characterization of H_2:CH_4 dissociation level in microwave ECR plasma source by fibre-optic OES

摘要

Spatially resolved optical emission spectroscopy (SR-OES) was used to investigate microwave activated H_2/Ar/CH_4 plasma under conditions of the electron cyclotron resonance (ECR). The chemistry and composition of the gas phase were studied using self-designed fibre-optic system with echelle type spectrometer during CVD deposition of polycrystalline diamond. One-dimensional intensity profiles of the main species were collected along the vertical axis of chamber. The dominant species in the flux, originating from excited hydrogen and hydrocarbons, were identified as H, H~+, CH and CH~+; they are crucial for the diamond deposition process. The effect of ECR on the spatial distribution of H_2 and CH_4 dissociation profiles was studied in depth. The influence of processing parameters (gas flow rates, input power, pressure and magnetic field level) on species excitation as a function of the distance above substrate was asessed. The obtained data can be used for the ECR system optimization.