Statistical analysis of the effect of deposition parameters on the preferred orientation of sputtered AlN thin films

A response surface statistical method was used to study the effects of deposition pressure, power and substrate temperature on the degree of preferred orientation of aluminum nitride films grown on Si (111) by dc magnetron sputtering. The AlN films were deposited at gas pressures ranging from 0.66 to 1.33 Pa, substrate temperature from 300 to 400 °C and power from 100 to 200 W. The degree of preferred orientation was evaluated and quantified using two-dimensional X-ray diffraction, which provides information on the out of plane (002) crystal alignment. The statistical method yielded a surface response curve in the parameter space and a correlation equation between the deposition parameters was obtained. Substrate temperature showed no significant effect upon texture quality for the temperature range studied. A surface response graph as a function of pressure and power was obtained. The main factor affecting texture quality was found to be a pressure-power interaction. The possible mechanisms that contribute to such correlation are discussed. Our best films yielded a rocking curve with full width at half maximum of 6.3°.