高周波反応性スパッタリング法による窒化物薄膜作製プロセスにおよぼすターゲット金属の影響

Abstract

In order to clarify the effect of target materials on the reactive sputtering process, we have characterized the hysteresis behavior of four kinds of target materials, Ti, Nb, Cr and Al. When highly reactive metals such as Ti and Nb were used as target, the hysteresis behavior appeared very clearly. On the other hand, the hysteresis became unclear when a low reactive metal such as Al was used. The hysteresis of Cr target was very small though the reactivity of Cr was not so low. This is attributed that the difference of sputtering yield between Cr metal and Cr-N nitride is smaller than that of the other metal.We have also investigated the optimum deposition conditions of sputtered Me-N films using the rf reactive sputtering apparatus equipped with a PEM (Plasma Emission Monitoring) control system for stabilizing the hysteresis behavior. The optimum condition for nitride films using highly reactive target metals such as Ti and Nb appeared to be near the unstable region of reactive sputtering process. The PEM system usedin the study was found to be very useful for depositing these nitride films. In the case of AIN films, the optimum condition was an excessive nitrogen partial pressure region. This difference in the optimum conditions is considered to be caused by the difference of reactivity of target metal and the stable metal-nitrogen alloy phase.