Effect of DC Bias on the Plasma Properties in Remote Plasma Atomic Layer Deposition and Its Application to HfO2 Thin Films

Abstract

Direct current biased remote plasma atomic layer deposition (RPALD) was developed and applied to deposit HfO2 films, and these results were compared with those of RPALD. DC biased RPALD system exhibits effective features that allow the plasma density to be controlled by dc bias. When dc bias was applied to the radio frequency (RF) plasma, the amount of free radicals and ions were increased. The electrical properties of HfO2, such as the effective oxide thickness (EOT) and the breakdown voltage, were improved by dc bias when compared to those of RPALD. This is due to the relatively high amount of free radicals controlled by dc bias.