Elimination of arcing in reactive sputtering of Al₂O₃ thin films prepared by DC pulse single magnetron

The article reports on the elimination of arcing in the DC pulse reactive sputtering of Al₂O₃ thin films using a single unbalanced magnetron operating at relatively high target power density W_ta ranging from ∼10 to ∼50 W/cm²; W_ta is the target power density averaged over the pulse length. Correlations between pulse length Ï, pulse-off time t_off, repetition frequency f_r and arcing at the target surface were investigated in detail. Undesirable damage of sputtered alumina film due to arcing is demonstrated. It is shown that the length of pulse-off time t_off is of key importance for elimination of arcing in pulse reactive sputtering of electrically insulating compounds using a single magnetron. Reactive magnetron sputtering is a very useful technique for preparation of Al₂O₃ films. However, to produce a good quality film the arcing at the target surface must be eliminated. Our investigation shows that transient phenomena connected with the pulse switch-off are important in the elimination of arcing. It is shown that Al ₂O₃ films with smooth surface can be reactively sputtered also at low frequency, high duty cycle and relatively high target power density.