The Study Of Helicon Wave Discharge And Preparation Of Diamond-like Carbon Film

The application of integrated circuit?IC?has deeply affected all aspects of society along with the rapid development of microelectronic technology.In particular,the improvement of integration level has accelerated the speed of knowledge-driven and informational economy.However,the conventional plasma source has not satisfied the need of production and processing because of the decreasing feature of dimension in IC devices and the improvement of integration level.As a new kind of high density plasma source,helicon wave plasma source has attracted much attention.Helicon wave plasma is generated in low temperature and pressure,it is a kind of right-hand polarized wave excited by a specific antenna surrounded on the walls of the quartz tube.The high density(about 10¹⁹m^-3)can be observed at 0.1 Pa,and the ionization rate in the center region of the plasma will be up to 100%.It will be widely applied in large scale integrated circuit technology,the MEMS processing,nanometer material preparation,surface modification and gas laser in the near future.This paper measured different plasma parameters?such as electron temperature?T_e?,ion density?N_i?,gas temperature?T_g?and so on?through Ar/N₂ helicon wave discharge by Langmuir probe,Optical emission spectra,Electrostatic Quadrupole Plasma.It was found that the N_i and T_e get the maximum(2.63×10¹⁹ m^-3 and 5.38 eV,respectively)when the flow rate ratio of N₂/Ar+N₂ was 50%under the same condition.At the same time,the T_g gradually decreased when increasing the N₂ flow rate used by lifbase software simulation of N₂⁺peak.The Ar/N₂ energy distribution showed that the Ar⁺and N⁺energy spectrum displayed all two peaks due to magnetic field restriction and bulk ions,ion-beam,respectively.According to the study of plasma parameters,the SiON thin film was prepared by nitridation using helicon wave plasma chemical vapor deposition.The structure and characteristics were measured by XPS,AFM and contact angle tester.It was found that the SiON films were constituted of Si-O-N and Si-N measured by XPS,AFM indicated that the surface of the film was very flat and smooth,and the RMS was less than 1.2 nm.The hydrophobic property increased obviously after nitridation on the surface of SiDiamond-like carbon?DLC?contains sp² graphite phase and sp³ diamond phase,and the graphite phase exists in the cross-linked network structure of diamond phase.Therefore,DLC has lots of excellent properties,such as high hardness,self-lubrication,good thermal conductivity and optical transparency.Now DLC has already been applied in mechanical,MEMS,optical and electrical devices and so on.In our experiment,DLC thin film was prepared on Si wafer through Ar/CH₄ helicon wave discharge.OES measured the intensity of some active radical such as CH,H_?,H_?,C₂ as a function of CH₄ flow rate.It was found that the CH and H were the deposition predecessor of DLC films.The work of H was to etch non-diamond constituent.C₂species in the plasma which forms more sp² hybridized bond on the surface of the films.The distribution of D peak and G peak was measured by Raman spectra.The visible and UV Raman were obtained to calculate Disp?G?as a function of CH₄ flow rate.It was found that the sp³ content was highest?about 30%?when CH₄ flow rate was65sccm.The SEM cross-sectional views of DLC films showed that the deposition rate was very high,and was about 54um/h when CH₄ flow rate was 85sccm.