Optimization and reliability characteristics of TiO/sub 2//HfO/sub 2/ multi-metal dielectric MOSFETs

Optimization of TiO/sub 2//HfO/sub 2/ bi-layer dielectric MOSFETs and their breakdown behaviors have been investigated for the first time. As the ratio of TiO/sub 2/ top layer increases, reduced EOT, reduced hysteresis, and improved transistor characteristics with increasing electron and hole mobility are observed. Distribution of a two-step breakdown characteristics suggest the breakdown occurs first in the HfO/sub 2/ bottom layer.