Electrical property improvement by Si doping for ZrO2 Based Capacitor using Atomic layer deposition

Abstract

Low leakage current is mainly requirement of DRAM capacitor to following narrow scale down on semiconductor industry. High-k material has wide energy band gap, which means it can reduce leakage current without thickness decreases. Replacing the conventional silicon dioxide gate dielectric with a high-κ material allows increased device performance without the associated leakage effects. Candidate of High-k" materials are hafnium dioxide (HfO2), zirconium dioxide (ZrO2) and titanium dioxide (TiO2) inherently has a dielectric constant or "k" above 3.9, the "k" of silicon dioxide. Zirconium dioxide (ZrO2) is widely used for high-k material on DRAM capacitor, because of thermal stability. However it has higher leakage current issue than HfO2. In this study, we confirmed electrical property improvement by Si doping for ZrO2 base capacitor. We used atomic later deposition (ALD) for Si-doped ZrO2 film. ALD process lots of advantage for capacitor, such as low process temperature, low impurity, excellent step coverage and good thickness control. Result shows proper Si doping makes to reduce leakage current.