Preparation And Tcr Properties Of Tantalum Nitride Films

With the development of electronic components towards integration,highfrequency,and miniaturization,thick film resistor devices are gradually replaced by thin film resistor devices in many fields.Tantalum nitride（TaN_x）is widely used as a thin film resistor material because of its excellent physicochemical stability and low temperature coefficient of resistance（TCR）.Our group has previously investigated the preparation process of high performance TaN_x films by magnetron sputtering and the effect of annealing process on TaN_x films.On this basis,this paper adopts magnetron sputtering technology to prepare buffer layer/tantalum nitride（TaN_x）thin films,and investigates the film properties by observing the film morphology,film structure,testing resistivity and TCR,and systematically studies the influence law of different buffer layers and annealing conditions on the properties of TaN_x thin films,as follows:Firstly,zinc oxide（ZnO）thin films were prepared by magnetron sputtering technique,and the preparation method of ZnO buffer layer and its influence law on TaN_x thin films were studied.The results show that the increase of argon flow rate and oxygen flow rate can reduce the deposition rate of ZnO films,and vice versa will significantly increase the deposition rate of ZnO.Meanwhile,air annealing of the buffer layer can further improve the ZnO（002）selective orientation and crystalline quality of the film,and effectively improve the film resistivity to optimize its role as a buffer layer.The crystallinity of the TaN_x films grown on the ZnO buffer layer was improved,and its TCR value increased from-78.0 ppm/°C to-64.7 ppm/°C.Secondly,ZnO buffer layer and TaN_x film were annealed to study the effects of different annealing processes on the properties of TaN_x film.The results show that the TCR value of tantalum nitride thin films can be optimized by annealing buffer layer in air,and this phenomenon is most obvious when the thickness of ZnO buffer layer is 500nm.For the annealing of TaN_x films,the TCR of the films can be improved on the thin ZnO buffer layer under different annealing conditions.After proper annealing process,the TCR of the films can be increased to-43.5ppm/℃.However,when the ZnO buffer layer is thicker,the TCR value of the film generally decreases due to the overall annealing.Finally,aluminum nitride（AlN）films were prepared by magnetron sputtering technique to investigate the preparation of AlN buffer layer and its effect on TaN_x films.The authors found that the increase in nitrogen flow rate can significantly reduce the deposition rate of AlN films.With the increase of AlN buffer layer thickness,the resistivity of tantalum nitride films decreased and the TCR value increased,and when the buffer layer thickness was 180 nm,the TCR value of the films increased to-55.6ppm/°C.The XRD results show that AlN（002）crystal phase grows prefertively with the increase of the thickness of AlN buffer layer,so the preferred orientation of Ta₂N（002）in the film can be realized by lattice matching.