Cryo-ALE of Si based on SF6 Physisorption
Résumé
Cryogenic Atomic Layer Etching (Cryo-ALE) has been presented in the previous J2C
editions as a different approach to achieve ALE of SiO2. In this process, C4F8 was first
used as a precursor chemical in the modification" step in order to physisorb on a cooled
SiO2 surface between -120C and -90C. The etching" step is then achieved by using an
Ar plasma with a low energy ion bombardment. Although satisfying results were obtained
with C4F8, the process does not allow high etching selectivity of SiO2 over Si and Si3N4
as the deposited CFx passivation layer is not thick enough to effciently passivate Si and
Si3N4 surfaces. Therefore, cryo-ALE based on SF6 physisorption was studied to extend
the use of this new type of process to other materials and to characterize its etching
properties.
The Cryogenic Atomic Layer Etching process concept will first be introduced in this
poster. The presentation will then focus on the experimentation methods and objectives
of this study.