Reactive-sputter etching-induced damage in MOS devices for VLSI/ULSI circuits.

Among the various plasma etching techniques Reactive-Sputter Etching (RSE) offers the highest anisotropy. The technique is therefore very important for submicron feature patterning of high density-MOS circuits. RSE of certain materials is done in an environment of very high energy ions and intense radiation. This process-induced radiation damage affects the generic reliability degradation of MOS circuits. In this paper we present our results on damage in thin gate oxides introduced by post-gate RSE steps. We have done this study for a large number of system parameters such as input power, self-bias voltage and different etching conditions. Our studies show that the RSE introduced damage depends on the self-bias voltage, plasma configuration and metallic surfaces close to the plasma.