HfOx as RRAM material - First principles insights on the working principles

作者：Clima Sergiu^*; Govoreanu Bogdan; Jurczak Malgorzata; Pourtois Geoffrey

来源：Microelectronic Engineering, 2014, 120: 13-18.

DOI：10.1016/j.mee.2013.08.002

• HfO2
• REAM
• Switching mechanism

First-principles simulations were employed to gain atomistic insights on the working principles of amorphous HfO2 based Resistive Random Access Memory stack: the nature of the defect responsible for the switching between the High and Low Resistive States has been unambiguously identified to be the substoichiometric Hf sites (commonly called oxygen vacancy-V-O) and the kinetics of the process have been investigated through the study of O diffusion. Also the role of each material layer in the TiN/HfO2/Hf/TiN RRAM stack and the impact of the deposition techniques have been examined: metallic Hf sputtering is needed to provide an oxygen exchange layer that plays the role of defect buffer. TiN shall be a good defect barrier for O but a bad defect buffer layer. A possible scenario to explain the device degradation (switching failure) mechanism has been proposed - the relaxation of the metastable amorphous phase towards crystalline structure leads to denser, more structured cluster that can increase the defect migration barriers.

• 出版日期2014-5-25