The Experimental Investigation Of Radio-frequency Bias Effects On Characteristics Of Inductively Coupled Ar Plasmas

Inductively coupled plasma (ICP) has been extensively used in plasma assisted processes. During recent years, people have applied radio frequency (rf) bias power in ICP to get high ion energy bombarding on substrate, and consequently the ion energy and plasma density could be controlled independently. In order to make a comprehensive study of the effect of rf bias power in Ar ICP, we have made axial, radial and fixed place measurement by using a single Langmuir probe, and investigated the effect of rf bias power on plasma parameters at different coil powers, different discharge pressures, different locations. Even the variation is not very big, but it has significant value for researching plasma processes.Chapter I is the exordium of this thesis, it briefly introduces the characteristics of low temperature plasma and basic structure of ICP.Chapter II is about experiment setup and diagnoses system.Chapter III shows that:1) when measured in axial direction, the plasma parameters varied with rf bias power. The change of electron density was remarkable at the upside of chamber but ion density was more uniform. As the rf bias power had heating effect on plasma, the electron temperature and plasma potential increased with bias power getting bigger.2) When measured in radial direction, the plasma parameters above substrate changed obviously. The parameters of place near substrate changed more obvious than the parameters of place away from substrate. The substrate with bigger diameter caused significant variation of plasma parameters comparing with substrate with smaller diameter, and also made the plasma parameters uniform at radial direction.3) When measured at fixed position, the powers of plane coils (ICP power) affect the changing trends of those plasma parameters versus rf bias power directly. a) When ICP power is above 100 W, with the enhancement of bias power, electron density decreases, and electron temperature and plasma potential increase. b) When ICP Power is between 50 W and 70 W, electron density basically keeps constant as the bias power increases, but electron temperature and plasma potential are getting larger; c) When ICP power is below 50 W, as the bias power rises, electron density increases, electron temperature decreases, and plasma potential increases.4) If increase the distance of discharging area, the variation of electron density and temperature with rf bias power would getting small, and the change of plasma potential would not be obvious. And the lager of the distance, the bigger of electron density, the lower of electron temperature and plasma potential at high intensity discharge and medium intensity discharge.