INFLUENCE OF DISCHARGE POWER LEVEL AN THE PROPERTIES OF HYDROXYAPATITE FILMS DEPOSITED ON TI6A14V WITH RF MAGNETRON SPUTTERING

The effects of discharge radiofrequency (RF) power and film thickness were studied on the characteristics of Ca-5(PO4)(3)OH (hydroxyapatite) thin films fabricated by RF magnetron sputtering. The structure and c hemical composition were investigated with alpha-step (thickness), sca nning electron microscopy (SEM), X-ray diffraction (XRD), Rutherford b ackscattering spectrometry (RES), and infrared absorption spectrometry (FTIR). The films were analyzed assputtered and after annealing at 55 0 degrees C under argon flow. SEM showed that the film surfaces had no cracks or other defects. X-ray diffraction showed that the deposited films were amorphous with low-discharge RF power, and crystalline with high-discharge RF power. After annealing, all the films had the same crystalline structure as apatite. However, the RES measurements reveal ed that all films had a higher calcium-phosphate ratio than standard s ynthetic hydroxyapatite. Furthermore, statistical testing of the RES d ata revealed the existence of only a weak correlation between the Ca/P ratio and the discharge power level. Although an sputtered films show ed phosphate bonds in the infrared spectrum, only after annealing did the OH bonds of hydroxyapatite become visible. (C) 1995 John Wiley and Sons, Inc.