Metal transport and loss in ultrathin hafnium aluminate films on silicon studied by low, medium, and high energy ion beam analyses

Abstract

Metal transport and loss induced by thermal annealing in ultrathin HfAlxOy films deposited on Si by atomic layer deposition were investigated by ion beam analysis. It was observed that rapid thermal annealing at 1000 °C induces decomposition of the aluminate films leading to Hf and Al losses mainly into the gas phase. It was possible to avoid this undesired decomposition effect by performing a postdeposition nitridation in NH3 at 850 °C prior to the rapid thermal annealing step. The role of nitridation is discussed in terms of the profiles of incorporated N, before and after rapid thermal annealing, as determined by narrow resonant nuclear reaction profiling.