NEW THIN-FILM FABRICATION TECHNIQUE USING A SUBSTRATE EXCITED BY SAW

We introduce a new thin film fabrication technique which uses a surface phonon mode substrate excited by surface acoustic waves (SAW) to control the morphology of very thin films. Permalloy films and Co-Cr-Ta films of 3001 thickness were prepared by d.c. magnetron sputtering onto LiNbO3 single crystal substrate excited by SAW. By scanning electron microscopy (SEM) and scanning tunneling microscopy (STM) observations, the structure of films was found to be drastically changed by SAW excitation as a function of excited amplitude. Especially at the critical excitation voltage, film structure consists of homogeneous grain form and very fine grain size is realized. In the Co-Cr-Ta sputtered films fabricated at this critical SAW excitation voltage of 8V, the value of Hc takes minimum value of about 5 Oe, which is 2 orders lower than that of the films fabricated without SAW excitation. In the Mo-permalloy films fabricated at this voltage, stress free films are fabricated and excellent soft magnetic property are realized. As these results shows, a new thin film fabrication technique which uses substrates excited by SAW is a useful technique for controlling the morphology and magnetic properties of thin films. © 1990 IEEE