| Summary: | 碩士 === 長庚大學 === 機械工程研究所 === 98 === 英文摘要In this research, a real-time plasma diagnosis system of optical emission spectroscopy (OES) and Langmuir is developed to monitor the plasma of our microwave plasma enhanced chemical vapor deposition (MPECVD) system for probing the physical properties and chemical compositions of the plasma. Under specific conditions (flow rates of reacting gases, ratio, pressure, and power of microwave) of the MPECVD system, the electron temperature, and plasma density are measured by Langmuir probe, and the species of the plasma are identified by OES. For example, when the methane of constant flow-rate is mixed with different gases (e.g. hydrogen, oxygen, and nitrogen), the electron temperature, plasma density and the species of plasma (e.g. H、H、CH、C2) are measured with respect to different system conditions (microwave power, pressure, gas flow rate). Multi-channel OES system is used, where each channel covers different wavelength range with different resolution. These spectroscopes are calibrated by using the well-known spectrum of the plasma of single gas (e.g. H2). The spectra of radicals (e.g. OH) are characterized by measuring the plasma of two mixed gases (e.g. H2, O2). Finally, we use OES and Langmuir probe to monitor the dynamic changes of plasma under varying conditions, and correlate these data with the system conditions. Keyword: microwave plasma enhanced chemical vapor deposition (MPECVD), Langmuir probe, optical emission spectroscopy (OES), real-time, characteristic wavelength.
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