Impact of Embedment of Cu/TaO_x/Ru on Its Device Performance

Abstract

In our previous work, electric performance of Cu/TaO x /Ru has been found to be inferior to that of Cu/TaO x /Pt device. The poor switching properties of the Ru device have been attributed to the degraded inertness properties of the Ru electrode as a stopping barrier for Cu as compared to the Pt electrode. To study this degradation effect further, we have manufactured two nominally identical Cu/TaO x /Ru devices however differently embedded on the Si wafer. While device A is characterized by the layer sequence SiO 2 -730nm/Ti-20nm/Ru-50nm/TaO x -25nm/Cu-150nm device B has an additional TaO x -30nm layer inserted between SiO 2 and Ti layers. We find the electric behavior of the two devices markedly different. Thus the embedment of the device has a major impact on the intrinsic device performance. We explain the difference to be due to high local temperatures >600 o C in the device during the switching that cause species interlayer diffusion and trigger undesired chemical reactions.