The effects of postdeposition annealing on the crystallization and electrical characteristics of HfO_2 and ZrO_2 gate dielectrics

摘要

This study examined the effects of postdeposition annealing (PDA) on the electrical characteristics of atomic layer deposited ZrO_2 and HfO_2 films using similar precursors and process conditions. After PDA at 600°C, the insulating properties of ZrO_2 improved but those of HfO_2 deteriorated. The improved insulating properties of ZrO _2 were attributed to the negligible increase in the interfacial layer thickness and an amorphous to tetragonal phase transformation. In addition, the degraded insulating properties of HfO_2 after PDA at high temperatures were attributed to an abrupt increase in the interfacial layer thickness and the generation of conducting paths through the grain boundaries.