CdSe Embedded ZrHfO Gate Dielectric Nonvolatile Memories - Charge Trapping and Breakdown Studies

MOS capacitors composed of nc-CdSe embedded ZrHfO high-k gate dielectric stacks were fabricated and investigated on the charge trapping and breakdown mechanisms. The interface layer between the high-k film and Si wafer was transformed to a more SiO2-like HfSixOy group after the inclusion of nc-CdSe layer. The frequency-dependent conductance-voltage measurement result shows that part of the trapped charges were loosely trapped at the nc-CdSe/ZrHfO interface and easily tunneled back to the Si substrate under low frequency measurement condition. Compared with the control sample, the nc-CdSe embedded sample has a larger leakage current and a higher breakdown voltage due to the formation of new leakage paths and a larger physical thickness. The trapped charges can be retained in the nc-CdSe site after the breakdown of the high-k film.