Cathode Target Sputtering Behavior In High Power Pulsed Discharge And Thin Film Deposition

Magnetron sputtering technologys are widely used in film preparation fields,with the development of industrial technology,traditional magnetron sputtering has been unable to meet the high performance requirements of thin film.High Power Pulsed Magnetron Sputtering(HPPMS)provides high peak power,high target particle ionization rate,low average power,and prepares dense smooth films which has better structure and properties than direct current magnetron sputtering(dcMS).Plasma behavior will be much different between dc MS and HPPMS,and plasma behavior has a great influence on the coating quality and deposition process control,which must be carried out independent research in order to obtain the relevant knowledge.Therefore,in high power pulsed diode sputtering,HPPMS and high power pulsed reactive magnetron sputtering,evolution of target current and plasma behavior was investigated by adjusting external parameters,and then film was prepared by HPPMS to verify that high quanlity film can be obtained by this technology.In high power pulsed diode sputtering,discharge behavior and plasma density were investigated taking Cu as an example,film deposited for discussing the film growth mechanism.The results showed that the gas pressure,voltage,pulse width and pulse frequency affected target current and the substrate current.Plasma density increases with Argon pressure,target voltage,pulse width,pulse frequency and substrate bias voltage increasing.Deposition rate decreases with the distance between target and substrate increasing.Surface morphology was different in different distance.The film grain has a tendency to grow up when pulse width increases,the film grains grow up and combine to form a continuous film.Substrate temperature and diffusion phenomenon strongly influence the film surface morphology,with pulse width increasing,particles arrived to film surface can not sufficientlydiffuse which result in holes in the films.Dense film can be obtained in appropriate pulse width and pulse frequency.Sputtering bahavior was studied in high power pulsed reactive magnetron sputtering.Taking typical Ti N film as an example,studies were carried out to investigate the influence of process parameters on film structure and properties.Target current was influenced by target voltage,magnetic field,pulse frequency and pulse width,but little by N2 pressure.Plasma density is in the order of 1017m-3 magnitude,which affacted by target voltage,N2 pressure and magnetic field.Honeycomb-like(mountain-like)morphology appeared in low target voltage and manetic field intensity,another one was etched relatively flat area and molten eruptions morphology coexistence on target surface.Sputtering target ions and self-sputtering behavior of target ions are crucial in HPPMS and high power reactive sputtering,which not only can increase the plasma density,but also can effectively avoid the hysteresis generation in reactive sputtering.Compared to typically triangular pyramid pattern deposited in dc MS,films deposited by high power pulsed reactive sputtering are uniform,fine equiaxed grain in nanoscale.Hardness of the Ti N films are a dozen GPa,the highest film hardness is 19 GPa when the N2 partial pressure is 0.6Pa,target voltage is 900 V.Film adhesion strength increased with N2 pressure decreasing,was stable with target voltage prepared by high power pulsed reactive sputtering,and was higher than film deposited in dc MS.Sputtering bahavior was discussed in HPPMS,and taking Solid Oxide Fuel Cell interconnector protection film as an example to investigate the influence of process parameters on film structure and properties.Results indicated that target current was affected by pulse width,target voltage,sputtering time and magnetic field.Discharge is divided into four stages,sputtering threshold,sputtering yields and ionization energy affacted target current in different stages.Plasma density is in the order of 1017m-3 magnitude.Sputtering yield and ionization energy plays a major role in sputtering target volume,higher sputtering rate was obtained in high sputtering yield and low ionization energy material.Sputtering time and magnetic field had little effect on target surface morphology,crater morphology appeared in high voltage in Cu target.Interconnector protection films in Solid Oxide Fuel Cell(SOFC)deposited by HPPMS are dense,smooth and fine grain size,which still have good surface quality after high temperature annealing.Films are good at long-term stability and Cr barrier properties.A battery which was packaged using the cathode and the connector covered with protection film obtained stable output.Through the sputtering behavior investigation and film deposition in high power pulsed sputtering,pulse parameters,target voltage,magnetic field and target material will affect the target current,plasma density and surface morphology.Sputtering threshold,sputtering yield and ionization energy affacted sputtering behavior,sputtering target ions and self-sputtering behavior of target ions are crucial in HPPMS.Films deposited by high power pulsed sputtering are smooth,dense and fine grain size as high plasma density,excellent performance compared to films prepared by dc MS,and the film structure can be modulated.