RT info:eu-repo/semantics/article
T1 Microscopic origin of the acceptor removal in neutron-irradiated Si detectors - An atomistic simulation study
A1 López Martín, Pedro
A1 Aboy Cebrián, María
A1 Santos Tejido, Iván
A1 Marqués Cuesta, Luis Alberto
A1 Ullán, Miguel
A1 Pelaz Montes, María Lourdes
K1 Silicon
K1 Silicio
K1 Atomistic simulations
K1 Simulaciones atomísticas
K1 Irradiation
K1 Irradiación
AB The improved radiation hardness of p-type Si detectors is hindered by the radiation-induced acceptor removal process, which is not fully understood yet. Through atomistic modeling of displacement damage and dopant interactions, we analyze the acceptor removal under neutron irradiation, providing physical insight into its microscopic origin. Our results show that the fast decay of the effective dopant concentration (Neff) at low irradiation fluences is due to B deactivation caused by Si self-interstitials. The intriguing increase of the acceptor removal parameter with the initial dopant concentration (Neff,0) is explained by the limited number of mobile Si self-interstitials that survive annihilation and clustering processes. The sublinear dependence of the removal parameter on Neff,0 is associated to the inhomogeneity of damage for low Neff,0 and the formation of B-interstitial clusters with several B atoms for high Neff,0. The presence of O and C modifies B deactivation mechanisms due to the key role of BiO defects and the trapping of vacancies and Si self-interstitials, but for the impurity concentrations analyzed in this work ([O] >> [C]) it has little effect on the overall amount of removed acceptors. At high irradiation fluences, the reported increase of Neff is attributed to the formation of defect-related deep acceptors. From the analysis of the defect concentrations resulting from neutron irradiation and the occupancy of small clusters with acceptor levels reported in literature, we point out the tetra-vacancy cluster as one of the main contributors to Neff with negative space charge.
PB Elsevier
SN 1359-6454
YR 2022
FD 2022
LK https://uvadoc.uva.es/handle/10324/55603
UL https://uvadoc.uva.es/handle/10324/55603
LA eng
NO Acta Materialia, 2022, vol. 141, 118375
NO Producción Científica
DS UVaDOC
RD 22-dic-2024