PREFERRED ORIENTATION AND MICROSTRUCTURE OF NI-ZN-CU FERRITE THIN-FILMS DEPOSITED BY RF MAGNETRON SPUTTERING

We have investigated the effects of process parameters such as rf power, substrate, and gas pressure P(Ar) on preferred orientation, microstructure, and magnetic properties of Ni-Zn-Cu ferrite thin films deposited by conventional rf magnetron sputtering. The texture structure was developed in the ferrite filsm deposited on the SiO2/Si(100) substrate at low rf power conditions. The ferrite film on the Si(111) substrate always had (111) texture irrespective of process parameters due to lattice matching, but the texture of the ferrite film on SiO2/Si(100) changed from (111) to (100) and finally returned to (111) orientation again with decreasing P(Ar). Such behavior would occur presumably due to the characteristic atomic stacking sequence corresponding to a given condition of the ion bombardment. The ferrite films deposited at low P(Ar) had a denser microstructure consisting of tightly packed columnar grains with a smoother surface, better adhesion to the substrate, and better crystallinity than those at high P(Ar). H(cparallel-to)) of ferrite film deposited at low P(Ar) was larger than that at high P(Ar) and also larger than H(cperpendicular-to) of the deposited at the same P(Ar) because larger compressive stress was induced at low P(Ar) than at high P(Ar).