Comparison of HfSiO_x 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.

Atomic layer deposition of B2O3/SiO2 thin films and their application in an efficient diffusion doping process

“…In the case of using H 2 O, however, SiO 2 lms were not grown due to the lack of reactivity, which agrees well with the previous report using SAM-24 elsewhere. 22 Meanwhile, for ALD B 2 O 3 lms, the saturated growth rate when using O 2 plasma under saturation conditions is $0.4 Å per cycle, which is slightly higher than that when O 3 is used ($0.35 Å per cycle) as seen in . The increased growth rate using O 2 plasma might be attributed to higher reactivity of oxygen radicals.…”