| AVS 61st International Symposium & Exhibition | |
| Plasma Science and Technology | Monday Sessions |
| Session PS-MoA |
| Session: | Advanced FEOL/Gate Etching |
| Presenter: | Maxime Garcia Barros, STMicroelectronics, France |
| Authors: | C. Arvet, STMicroelectronics, France S. Lagrasta, STMicroelectronics, France M. Garcia Barros, STMicroelectronics, France S. Barnola, CEA, LETI, MINATEC Campus, France N. Posseme, CEA, LETI, MINATEC Campus, France F. Leverd, STMicroelectronics, France |
| Correspondent: | Click to Email |
Today, the choice of chemistry for nitride spacer etching is a CH3F/O2/He based chemistry. But such chemistry leads to 10A and 15A silicon and silicon germanium consumption, respectively. Furthermore the remaining carbon at the silicon or silicon germanium surface can lead to a poor silicon surface quality which does not allow the film regrowth. The optimization of this process is not enough reliable in order to be used in production for the FDSOI 14 nm technologies.
In this context, we investigated the impact of SiCL4 addition to CH3F/O2/He/CH4 chemistry.
Ellipsometry measurements performed on blanket silicon nitride and silicon germanium film allow us to investigate two essential points for the FDSOI 14 nm technologies:
-The resist consumption
-The opportunity to obtain an infinite selectivity of silicon nitride to silicon germanium.
Complementary XPS and FTIR analyses have been performed for a better understanding of the etch mechanisms and will be presented.
These results have been confirmed on patterned structures. TEM analyses have shown no silicon germanium recess with no foot formation after silicon nitride spacer etching and wet cleaning. Finally, the compatibility of this new etch chemistry on epitaxial growth quality will also be presented.