유도 결합 플라즈마에서 쉬스 경계면과 챔버 중심의 밀도비에 대한 실험적 연구

Abstract

The plasma densities at the edge and center of a chamber in an inductively coupled plasma were measured by using a floating harmonics method, which can measure ion density without changing sheath formation on the chamber edge. Measurements have been done in argon gas ranging between 3 mTorr and 30 mTorr. The ratios between edge and center density has been compared with theoretical ones. The Measured edge-to-center density ratios agree well with the tendency of theoretical values. It was found that the edge density has the maximum values at 10mTorr, regardless of input powers. This can be understood by considering the dependence of the edge-to-center density ratio and center density on pressure.