Experimental Study Of Ar/O₂in The Pulse-modulated Inductively Coupled Plasma Discharge

Pulse-modulated inductively coupled plasma (pulse-modulated ICP) source is based on inductively coupled plasma (ICP). The difference is that the radio-frequency (RF) power source of ICP source is pulse-modulated. That is to say, pulse-modulated acts as an automatic switch of the RF power source. The power of the RF source input periodically to stimulate the plasma generation. Pulse-modulated ICP source still has the advantages of the ICP source, such as high plasma density, low pressure and simple device structure. With the increasing of the size of Si substrate, the ICP source presents some shortcomings, such as substrate damage, charge accumulation on the substrate. Pulse-modulated ICP can solve these problems well. So the study of pulse-modulated ICP is meaningful.Therefore, the purpose of this study is to research the characteristic spectrum line intensity of the pulse-modulated ICP with changes in experimental parameters by using the optical probe on the planar coil inductively coupled plasma source device, so as to analyze the impact of experimental parameters on the intensity of emission spectrum.The first chapter of the thesis reviews the classification of the low-temperature plasma sources and the corresponding features. In particular, a detailed description of the ICP excitation principle and the impact of pulse-modulated on the ICP are introduced. Secondly, it introduces several commonly used diagnostic methods in the study of low-temperature plasma. Third, I summarize previous study on the pulse-modulated ICP. Finally, the structural of the thesis is characterized.In Chapter2, the pulse-modulated ICP source used in this study and the diagnostic instruments devices are described in detail.In Chapter3to5, the results of the experimental study of pulse-modulated ICP Ar, O2, Ar/O2discharge are described respectively by using optical probes. The results showed that, in the pulse-modulated ICP Ar and O2discharge, the characteristic spectrum line intensity of Ar and O2increase monotonically with pulse duty ratio, power. With the increasing of pulse repeated frequency, there is no obvious change of the spectrum intensity. In the Ar/O2pulse-modulated inductively coupled plasma, we use optical probe to diagnose the spectrum intensify of Ar and O atom. The spectrum intensify of Ar at750.4nm and811.5nm has been obtained versus the content of O2, the applied RF power, pulse duty ratio, pulsed repeated frequency, pressure and the position of radial. The same measurement has been taken for O atom spectrum at777.4nm and844.6nm. The results show that the spectrum intensity of Ar and O atom increase firstly with the increasing of O2content and decrease later, and the spectrum intensity of Ar and O atom increases monotonically against the input power, and the duty ratio. The change of the spectrum intensity of Ar and O atom is not obvious with the pulsed repeated frequency. In addition, under the same conditions, there is a comparison between inductively coupled plasma and pulse-modulated inductively coupled plasma. The result shows that the time-averaged spectrum intensity of pulse-modulated inductively coupled plasma is lower than inductively coupled plasma.