Abschlussarbeiten - Master
Creation of top down produced SiGe Nanowires by Plasma Etching
Art der Abschlussarbeit
Master
Autoren
- Shakeel, Shahrukh
Betreuer
- Prof. Dr. rer. nat. Johann Wolfgang Bartha
- Dr.-Ing. Karola Richter
Weitere Betreuer
M.Sc. Khan (HZDR)
Abstract
Silicon-Germanium (SiGe) has higher carrier mobility and ability to be integrated into existing Silicon
technology. Nanowires (NW) possess the potential to be the building blocks of future technologies.
Therefore, NW and SiGe based devices are under extensive research. This work is aimed at the
development of an Inductively coupled plasma - reactive ion etching (ICP-RIE) based process for the
fabrication of smooth SiGe NWs. ICP-RIE is known to give anisotropic etch profiles and NWs with vertical
sidewalls can be created using it. At very low device dimensions, even surface roughness amounts to a
significant fraction of the device. Therefore, the atomic scale control is necessary to reduce the roughness
induced by the etching processes. This can be achieved by atomic layer etching (ALE), which is known to
provide atomic-scale precision. This work focuses on employing SF6/C4F8/O2 gas mixture at the ambient
temperatures to fabricate the horizontal SiGe NWs with smooth vertical sidewalls on the Silicon-
Germanium-on-Insulator (SiGeOI) samples. Hydrogen Silsesquioxane (HSQ), a high resolution negative
tone electron beam lithography resist is used to define the sub-15 nm nano-patterns. It also acts as an
etch mask. The HSQ nano-patterns are transferred into SiGe layer by the etching process developed using
the ICP-RIE. The diameter of these NW is further trimmed down to sub-12nm using the ALE process. The
effects of various ICP-RIE parameters on the etch profiles and the effect of ALE cycles on the NW
dimensions and the roughness are examined.
technology. Nanowires (NW) possess the potential to be the building blocks of future technologies.
Therefore, NW and SiGe based devices are under extensive research. This work is aimed at the
development of an Inductively coupled plasma - reactive ion etching (ICP-RIE) based process for the
fabrication of smooth SiGe NWs. ICP-RIE is known to give anisotropic etch profiles and NWs with vertical
sidewalls can be created using it. At very low device dimensions, even surface roughness amounts to a
significant fraction of the device. Therefore, the atomic scale control is necessary to reduce the roughness
induced by the etching processes. This can be achieved by atomic layer etching (ALE), which is known to
provide atomic-scale precision. This work focuses on employing SF6/C4F8/O2 gas mixture at the ambient
temperatures to fabricate the horizontal SiGe NWs with smooth vertical sidewalls on the Silicon-
Germanium-on-Insulator (SiGeOI) samples. Hydrogen Silsesquioxane (HSQ), a high resolution negative
tone electron beam lithography resist is used to define the sub-15 nm nano-patterns. It also acts as an
etch mask. The HSQ nano-patterns are transferred into SiGe layer by the etching process developed using
the ICP-RIE. The diameter of these NW is further trimmed down to sub-12nm using the ALE process. The
effects of various ICP-RIE parameters on the etch profiles and the effect of ALE cycles on the NW
dimensions and the roughness are examined.
Schlagwörter
-
Berichtsjahr
2020