Study On Microstructure And Magnetron Sputtering Deposition Properties Of W/Re Alloy Target Prepared By Vacuum Sintering

Tungsten(W)has the advantages of high melting point,high conductivity,high electron migration resistance,high electron emission coefficient and excellent high temperature stability.Tungsten targets have been widely used in the electronic information industry.However,tungsten and tungsten alloy high-end targets have strict requirements on their grain size,uniformity and density,so their preparation technology is a hot and difficult research topic at home and abroad.In this paper,W target with fine grain and uniform composition was prepared by powder metallurgy.And Re was added to inhibit the growth of grains during the long-term high-temperature vacuum sintering process and increase the density of the target.The purpose of this article is to carry out systematic research on the selection of raw materials and sintering process on the basis of existing mature technology and production of tungsten through powder metallurgy,so as to develop a new W/Re alloy target.This paper discusses two methods,blender mixer and NH₄Re O₄,to prepare W-Re powder(with 1wt.%,5wt.%and 10wt.%content of Re).The particle size distribution and average particle siz eof this two powders are tested by laser particle size analyzer and the morphologies of powders are observed by SEM.It was found that W/Re composite powder prepared by chemical reduction method was more uniform and had smaller particle size than that prepared by mechanical method.In contrast,reduction method of NH₄Re O₄is considerd to be the best way.Pure W and W/Re alloy(with 1wt.%,5wt.%and 10wt.%content of Re)was fabricated by vacuum sintering.The relative density of W/Re alloy were tested.As content of Re increasing from 1wt.%to 10wt.%,the relative density of W/Re alloy increased from 96.2%to 98.4%.W/Re alloys prepared by vacuum sintering grows preferentially along(110)direction through XRD,SEM EPMA and EBSD.Single W phase without Re phase or any other intermetallic compounds was found in W/Re alloy.And Re element was completely dissolved and evenly distributed in the W matrix.In addition,growth of W grains was hindered for the solid solution strengthening effect of Re element.That reduces the average grain size of W/Re alloy and improves the uniformity of grain size.The grains of pure W and W/Re alloy target are polygonal,and the grain orientation of them are not uniform.As the Re content increases,the proportion of particles of<111>crystallographic direction families decreases significantly,indicating that the grain orientation of W/Re alloy is more random than pure W.Therefore,Re is helpful to improve the magnetron sputtering deposition of W/Re alloy target.Magnetron sputtering experiments of W/Re and W target were carried out under different deposition pressure and sputtering power respectively.The film was observed by SEM.The adhesion between W/Re film and silicon wafer is great.The surface of W/Re film is flat and dense,and the grain size of W/Re film is fine.However,W film is discontinuous and incomplete.There are many cracks and large particles on the film.And the adhesion between the film and the silicon wafer is very poor.In addition,the increase of working pressure(0.2?0.5 Pa)also significantly improve the relative density,grain size and uniformity of the sputtering film,and the sputtering deposition rate will also be significantly improved.In addition,the intensity of the diffraction peak of the(110)crystal plane of the film gradually weakens,while the intensity of the diffraction peak of the(200)crystal plane gradually increases.And with the increase of sputtering power(30?80W),the surface of sputtering film becomes rougher and the grain size becomes larger,and the sputtering rate increases accordingly.