Comparison of HfSiOx Thin Films Deposited by ALD with Moisture Using Different Silicon Sources

Abstract

The scaling of semiconductor devices using various high-k materials has been investigated, and replacing the standard SiO2 gate dielectric by high-k material was a major step. Hafnium-based material is currently one of the preferred candidates. To improve integration of Hafnium into the gate dielectric, HfSiOx has been chosen for low power devices while HfZrOx is more common for high-performance applications. Using widely available processes, HfO2 can be deposited using amine or alkoxide based compounds and different reducing agents such as ozone, oxygen or moisture. However, depositing HfSiOx by Atomic Layer Deposition (ALD) with moisture is more challenging. Few or no available Silicon precursors are reactive with H2O alone to deposit SiO2 by ALD. This work is intended to present precursor solutions to deposit hafnium silicate using moisture as oxidant.