PULSE DURATION EFFECTS IN PULSE-POWER REACTIVE SPUTTERING OF AL2O3

Pulse-power reactive magnetron sputtering of dielectrics is a recently developed variation of d.c. sputtering. It avoids arcing caused by el ectrical charges which can appear on surfaces of dielectric films that grow on the target, substrate and surrounding walls. In the pulsed-po wer approach, a negative voltage is applied to the target during a tim e tau(on). During tau(on) the magnetron is on although its current may not reach a stable level until after a certain delay. The negative pu lse is followed by a pulse of small positive (reverse) voltage of dura tion tau(rev). During this time the residual plasma discharges the sur faces. In this work, the effects of durations tau(on) and tau(rev) and their frequency on reactive sputtering of aluminum oxide are investig ated. The influence of gas pressure and discharge current on pulsed-po wer sputtering is also studied. Experiments were done using a planar m agnetron and metal target. Optimum conditions were determined and are discussed. (C) 1998 Elsevier Science S.A. All rights reserved.