Monday, 1 October 2018: 11:10
Universal 7 (Expo Center)
A. A. Pil'nik, A. A. Chernov (Novosibirsk State University, Kutateladze Institute of Thermophysics SB RAS), T. V. Perevalov (Rzhanov Institute of Semiconductor Physics SB RAS, Novosibirsk State University), and D. R. Islamov (Novosibirsk State University, Rzhanov Institute of Semiconductor Physics SB RAS)
High-κ hafnium oxide is widely used in different electronic devices. The electronic properties of HfO2 (e.g. leakage currents, optics) are defined by defects and traps, namely by oxygen vacancies (VO). Generation of new defects leads to breakdown, increasing the leakage, that leads to the FET and FRAM degradation. On the other hand, active layers in RRAM devices use traps as precursors for HRS/LRS switch. The aim of the work is predicting the defect forming in dielectrics in strong electric fields using analytical, numerical and ab initio simulations. Despite the advances in computational performance, the ab initio simulations still require large time and efforts. Analytical and half-analytical solutions of the problem can be helpful in a way of predicting conditions for defect formation.The rate of new defect generation in the hafnium oxide with only one VO was calculated using the heat transfer equation with a strong positive loopback. The analytical and half-analytical solutions were found and compared with numerical ones. The most probable positions of new defect at specific electric field were found. These results were compared with ab initio (DFT) calculations of oxygen polyvacancy structure in monoclinic HfO2. It was found that the most favorable spatial configuration of an oxygen polyvacancy is a chain, where the next vacancy is formed near the already existing one, and no more than 2 removed O atoms are related to a Hf atom. Found distances between neighboring VO are (4.05-4.21) Å.
The work was supported by the Russian Science Foundation, grant #16-19-00002.
