The Effect Of Inductively Coupled Discharge On Single-and Dual-frequency Capacitively Coupled N₂（H₂/Ar Doped） Plasma

Low-temperature plasma plays an important role in materials processing, such as thin film deposition, etching, and surface treatments due to its controllable electron density and ion bombardment. Hence, Inductively coupled plasma(ICP) and very high frequency capacitively coupled plasma(VHF-CCP) have been developed for satisfying the requirement: controllable electron flux and energy and plasma uniformity with large area. Under these research background, a novel plasma source of inductively/capacitively hybrid discharge is proposed here. In this thesis, by using Langmuir probe and Optical emission spectroscopy techniques, we have in detail studied the dependence of discharge conditions on the electron properties of the hybrid plasma discharge through addition of H2(Ar) into N2 plasma environment and the influence of inductive coupling on the hybrid plasma discharge.First part of this thesis mainly focuses on the study of N2 inductively/capacitively coupled plasma doped by H2 with different pressure. It was shown that as inductive coupling with single frequency was coupled into single frequency capacitively coupled N2(H2 doped) plasma, the plasma density was enhanced, but the radical distribution was not uniform. As single frequency inductive coupling was coupled into dual frequency capacitively coupled N2(H2 doped) plasma, the enhancement of plasma density was also observed and the electron temperature and Debye length decreased. As increasing input power of single frequency inductive coupling, a higher electron density appeared at the center area with a better uniformity. These experimental results showed that inductive coupling power could modify the electron density along the radical distribution, and confine the plasma energy to increase the ionized efficiency.Second part of this thesis mainly focuses on the study of inductively/capacitively coupled plasma characteristics with different flow rate of Ar doped into N2. It was shown that as single frequency inductive coupling was coupled into dual frequency excited capacitively coupled Ar/N2 plasma, plasma density and electron temperature were higher than the case of dual frequency excited capacitively coupled plasma. As the input power of inductive coupling was larger than 200 W, electron energy possibility distribution function changed from dual Maxwell distribution into single Maxwell one, and the discharge mode from E mode into H mode. As increasing Ar flow rate, ionized efficiency enhanced as well as N2 spectral line intensity. Experimental studies showed that radical uniformity of hybrid plasma density was much better as Ar flow ratio was 80% and input power of inductive coupling was 200 W.The above mentioned inductively/capacitively hybrid N2(H2/Ar doped) plasma discharge have showed that coupling of single frequency excited inductive type into single or dual frequency excited capacitively coupled plasma not only prompt the increase of plasma density, but also improve the radical plasma uniformity. These studies exert significant roles in the field of material surface uniform treatment.