Which molecular characteristics enhance dissociation through the PEs and quench adverse effects of SEs?

Low-energy secondary electrons (SEs) play an important role in deposit formation in areas outside the primary electron beam focus. To unravel if these electrons initiate fragmentation primarily via dissociative electron attachment (DEA), silahexane and 1,1-dichloro-1-silahexane are compared. While the former is insensitive to DEA, this fragmentation channel is switched on by the presence of Cl in the latter:

• Elías H. Bjarnason, Benedikt Ómarsson, Nanna Rut Jónsdóttir, Ingvar Árnason,
  Oddur Ingólfsson:
  Dissociative electron attachment and dissociative ionization of 1,1-dichloro-1-silacyclohexane and silacyclohexane,
  International Journal of Mass Spectrometry 370 (2014) 39–43.

However, spatial control through suppression of DEA in the FEBID process is a small effect in these compounds due to contributions of dissociative ionization (DI):

• Ragesh Kumar T P, Sangeetha Hari, Krishna K Damodaran, Oddur Ingólfsson, Cornelis W. Hagen:
  Electron beam induced deposition of silacyclohexane and dichlorosilacyclohexane: the role of dissociative ionization and dissociative electron attachment in the deposition process,
  Beilstein J. Nanotechnol. 8 (2017) 2376–2388.8

In conclusion, it is likely that the contributions of DI in general cannot be switched off so that the effects of (SEs) may not be suppressed by tuning of the precursor. In contrast, when SEs can be prevented from exiting the surface by suitably tailored surface adlayers, their adverse effect can be diminished:

• M. Drost, F. Tu, F. Vollnhals, I. Szenti, J. Kiss, H. Marbach:
  On the Principles of Tweaking Nanostructure Fabrication via Focused Electron Beam Induced Processing Combined with Catalytic Processes,
  SMALL Methods 1 (2017) 1700095.