Speaker
Description
A new Ultra Fast Silicon Detectors production (UFSD3.2) has been produced
by Fondazione Bruno Kessler (FBK) in Trento, in collaboration with
University of Trento and National Institute of Nuclear Physics in Turin
(INFN); this production aims to improve the radiation resistance of the
multiplication layer (gain layer).
Previous FBK-UFSD productions (UFSD2 and UFSD3) demonstrated that the
co-implantation of carbon into the gain layer mitigates the acceptor
removal mechanism. In UFSD2 and UFSD3, the gain implant has been enriched
with carbon in a range of dose 1C-10C [a.u.]. The carbon enrichment showed
unexpected effects: the active fraction of boron into the gain implant
decreases with increasing carbon dose (carbon-boron capture); the
intrinsic radiation resistance of carbonated gain layers is better for
carbon dose 1C than higher doses.
In UFSD3.2, a carbon dose in a range 0.4C-1C has been implanted, in the
order to identify the optimal carbon dose that maximizes the radiation
resistance and minimizes the carbon-boron capture.
In this contribution: we will report a mapping of carbon-boron capture in
a range of carbon dose 0.4C-10C; we will show the acceptor removal
coefficients measured on gain implants enriched with carbon doses 0.4C,
0.6C, 0.8C and 1C, irradiated with neutrons up to fluence of 2.5E15n_eq/cm^2.
Our studies show a link between the dose where carbon-boron capture starts
and that that makes the most radiation resistant gain implant
