In AlN films prepared by the facing target system, a decrease in degre
e of c-axis orientation, film coloring and film cracking or peeling fr
om the substrate were observed. This film degradation is thought to be
related to insulative films in general. In order to clarify how these
phenomena are induced, we prepared samples under various sputtering c
onditions; i.e., by changing target holders, placing a ground mesh in
front of the substrate and using a positively biased electrode. It is
confirmed that plasma exposure severely influences c-axis orientation
of AlN films. To decrease this influence, it is important that electro
ns flow adequately into the anode.