Equivalent oxide thickness scalability of Zr-rich ZrHfO2 thin films by Al-doping

Abstract

With ultra-miniaturization of dynamic random-access memory (DRAM), it is very important to achieve equivalent-oxide-thickness (EOT) scaling of capacitors using materials applied to mass production. Compared to ZrO2, Zr1-xHfxO2 has a high possibility of improved electrical properties by doping in wide composition ranges. Therefore, we investigated the effect of Al-doping on electrical properties of Zr-rich Zr1-xHfxO2 thin films. Up to Al-doping of 2.1%, the leakage current was significantly improved without degradation of the dielectric constant, and it was possible to reduce the EOT by 0.12 nm in the leakage current specification applicable to DRAM capacitors.