Development of Crystallographic Texture in RF Sputter Deposited CoCrTa/Cr Thin Films

Abstract

It is well known that Cr sputtered on glass or NiP/Al substrates has either the (002) or (110) crystallographic texture (depending on the substrate temperature) and that the Co-alloy layers which are deposited on the Cr underlayers have either the (1120) or (1011) textures respectively. However, the dependence of the crystallographic textures on other sputtering parameters is not clear. We report here on the study of the dependence of crystallographic textures of CoCrTa/Cr films on substrate bias. It is found that both Cr (110) and Cr (002) textures can form at elevated temperature, depending on the substrate bias. The development of the crystallographic texture is discussed with a model. It is also found that the epitaxy of CoCrTa layer depends on the sputtering conditions of both the Cr and the CoCrTa layers. The extrinsic magnetic properties (such as Hc, S and S*) of thin films with various textures are also presented. By controlling the sputtering procedure, the effects of crystallographic textures on magnetic properties were separated from the effects of film morphology.