Gas temperature is an important parameter for the study of discharge modeling and in plasma etching process. We present neutral gas temperatures in Ar and Ar-Cl2 based ICP discharge measured by diode laser absorption spectroscopy (IRLAS) and Laser Induced Fluorescence (LIF) of argon metastable atoms. The temperature was deduced from the Doppler width of the 1s5→2p7 transition at 772.38nm. The line averaged temperature was determined by absorption spectroscopy, whereas the local gas temperature at the reactor centre was determined from the laser-excited 1s4←2p7 fluorescence at 810nm. The gas temperature was measured as a function of power (50–500W), pressure (5–90mTorr) and %Cl2 in Ar (0–90%). In pure Ar the temperature increase with gas pressure and RF power, reaching 600K at 90mTorr 500W, whereas in 90% Cl2 temperatures as high as 1500K were found.
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