Study On The Formation Mechanism Of Aluminum Nitride Film Based On Spark Discharge

With the development of miniaturization and integration trend of electronic components,the working environment of electronic components is getting more and more severe,and the heat generated in the work is emitted in a timely and effective manner,which is an important factor to ensure the stable work of electronic components and prolong their working life.Aluminum nitride(AlN)is considered as an ideal material for power electronic devices of the new generation due to its excellent thermal conductivity,reliable electrical insulation,low dielectric constant,non-toxic and thermal expansion coefficient matching with Si.In this paper,a new technology of producing aluminum nitride thin film on aluminum surface with high efficiency and low cost has been developed.It can be used in the industrial production of LED lighting,packaging of other power electronic devices.It is of great significance to improve the technical level of China's microelectronics industry and promote the progress of LED and other electronic industries.Firstly,by describing the chemical reaction principle of aluminum and nitrogen forming aluminum nitride and the chemical reaction conditions created by spark discharge,for analyzing the deposition process of aluminum nitride based on spark discharge.Based on the deposition process of aluminum nitride in a single spark discharge process,the influence of the deposited aluminum nitride on the dielectric breakdown of insulating gas in the spark discharge area during the redischarge and of discharge channel on the deposited aluminum nitride is analyzed.,and further explore the process mechanism of deposition of aluminum nitride film on large areas of the aluminum surface.Secondly,according to the basic theory of spark discharge,the physical and chemical properties of nitrogen and the related theory of heat transfer,the thermal model of discharge channel based on Gauss heat source is established,and the relevant parameters are revised.Using the finite element analysis software to simulate the thermal model of the discharge channel.By studying the distribution of transient temperature fields which is under the effects of heat flux density,speculating the rules which was according to the influence of discharge current and discharge pulse duration on the surface appearance of the discharge crater.Thus it was deduced that the surface appearance of the spark discharge channel on the surface of the aluminum substrate heat-affected zone will be useful.It will provide some theoretical guidance for optimizing the processing parameters and improving the efficiency and quality of the film.Finally,based on B30 CNC-EDM EDM shaping machine,the tool electrode and its rotating drive structure are designed and manufactured.In order to deposit large areas of aluminum-nitride thin films on the surface of aluminum substrate,in this paper,several kinds of electrode relative motion trajectories for aluminum nitride thin films are designed,and by the comparative analysis to choose the most suitable model.Furthermore,through the analysis of the probability of spark discharge in the surface of components to study the influence of various trajectory spacing on the uniformity of film formation,and obtain the optimization suggestion of tool electrode size,so that the discharge probability of the workpiece surface processing area was relatively balanced,and so as to get better uniformity of aluminum nitride film layer.Using the developed experimental devices to carry out the spark discharge of the aluminum electrode in the nitrogen atmosphere.By the method of X Ray Diffraction(XRD),testing the material which was generated on the surface of aluminum electrode.It will comes to the result that the matching degree of the highest material is the aluminum nitride,which is proved that the aluminum nitride thin film based on spark discharge technology is feasible.