Extremely clean sputtering process and microstructural properties of Ni-Fe films fabricated by this process

A new specialized sputtering machine which enables film deposition in an extremely clean atmosphere (XC-process) was constructed. Excellent base pressure less than 8×10^-12 Torr, which corresponds to about 1-10^-8 Torr l/sec in the build up rate, was realized in the process chamber. By use of both this new sputtering chamber and highly purified Ar gas with large flow rate, a very low impurity level during deposition is realized in the XC-process. This impurity level is about 4 orders lower than that of the normal sputtering process. By applying the XC-process to the fabrication of Ni-Fe films, grain size remarkably increases, and the highly coherent (111) crystal plane with lower fault density forms continuously from the initial layer to the top of the films