Asymmetric interaction of point defects and heterophase interfaces in ZrN/TaN multilayered nanofilms

Abstract

Materials with a high density of heterophase interfaces, which are capable of absorbing and annihilating radiation-induced point defects, can exhibit a superior radiation tolerance. In this paper, we investigated the interaction behaviors of point defects and heterophase interfaces by implanting helium atoms into the ZrN/TaN multilayered nanofilms. It was found that the point defect-interface interaction on the two sides of the ZrN/TaN interface was asymmetric, likely due to the difference in the vacancy formation energies of ZrN and TaN. The helium bubbles could migrate from the ZrN layers into the TaN layers through the heterophase interfaces, resulting in a better crystallinity of the ZrN layers and a complete amorphization of the TaN layers. The findings provided some clues to the fundamental behaviors of point defects near the heterophase interfaces, which make us re-examine the design rules of advanced radiation-tolerant materials.

Formation of Si-Rich Interfaces by Radiation-Induced Diffusion and Microsegregation in CrN/ZrN Nanolayer Coating

“…Otherwise, nonequilibrium compositional distribution is caused due to peculiarities of interfaces that act as a diffusion barrier for atoms and vacancies . The third factor was also reported as essential in the study of a similar nanoscale ZrN/TaN system . Nevertheless, the high-energy He ions were used (with low atomic mass) in that research, hence the strength of covalent bonds is dramatically different from our case.…”

“…57 The third factor was also reported as essential in the study of a similar nanoscale ZrN/TaN system. 16 Nevertheless, the high-energy He ions were used (with low atomic mass) in that research, hence the strength of covalent bonds is dramatically different from our case. Ultimately, it led to the more preferable He distribution in the TaN layer and vacancy accumulation at the interface.…”

“…One such a method is ion implantation, in particular Si implantation found popularity in integrated circuit processing to create p-type junctions near to the surface. − Threshold voltage control and good precision of implantation depth serve as beneficial accommodation to the required dopant distribution and concentration. Recently, ion implantation was introduced to heterostructure design enabling the creation of new phases and structures in the nanometer-thick layers. − …”

“…Because studies of nanolayer structure interaction with upcoming ions are limited and differed from one to another system, the resulting physical processes could vary dramatically. Lao et al 16 revealed an asymmetric nature of point defects in the ZrN/TaN system via the differences in the vacancy formation energies of continuous layers. This misfit leads to retained crystallinity in one phase and severe amorphization in the other.…”