Reliability of Post Plasma Oxidation Processed ALD Al2O3/Hf1-xZrxO2 Thin Films on Ge Substrates

Abstract

In this work, we have investigated the impact of Slot-Plane Antenna Plasma Oxidation (SPAO) on TiN/Hf1-xZrxO2/Al2O3/Ge gate stack with six different Zr content (0%, 25%, 33%, 50%, 75%, and 100%) in the dielectrics. The dielectrics were subjected to SPAO after the ALD deposition process prior to metal deposition. The equivalent oxide thickness (EOT), flat-band voltage (VFB), interface state density (Dit), C-V hysteresis, and leakage current (I-V) behavior were analyzed. It was observed that EOT decreases with Zr addition in HfO2 with up to 75% of Zr incorporation. While the devices with up to 75% of Zr demonstrated lower C-V hysteresis, flat-band voltage shift and mid-gap Dit tend to increase with decrease in EOT. With 100% Zr incorporation EOT increased significantly while reducing the mid-gap Dit. This behavior is mostly dependent on GeOx–like interfacial layer formation and defects at the interface.