Displacement Damage in Silicon Detectors for High Energy Physics

Abstract

In this paper, we review the radiation damage issues caused by displacement damage in silicon sensors operating in the harsh radiation environments of high energy physics experiments. The origin and parameterization of the changes in the macroscopic electrical sensor properties such as depletion voltage, leakage current, and charge collection efficiency as a function of fluence of different particles, annealing time, and annealing temperature are reviewed. The impact of impurities in the silicon base crystal on these changes is discussed, revealing their effects on the degradation of the sensor properties. Differences on how segmented and nonsegmented devices are affected and how device engineering can improve radiation hardness are explained and characterization techniques used to study sensor performance and the electric field distribution inside the irradiated devices are outlined. Finally, recent developments in radiation hardening and simulation techniques using technology computer-aided design modeling are given. This paper concludes with radiation damage issues in presently operating experiments and gives an outlook of radiation-hardened technologies to be used in the future upgrades of the Large Hadron Collider and beyond.

A review of advances in pixel detectors for experiments with high rate and radiation

“…Case (1) represents the case of a particle impinging close to perpendicularly to the pixel module leading to hit clusters of typically one or two pixels. Case (2) represents tracks impinging at steep angles, thus producing larger hit clusters with some directional information when properly treated by reconstruction algorithms, in particular when such clusters appear in several detector layers along a track. Exploiting the hit information this way could become important for hit assignment and track recognition in high track density at the LHC (see for example [14]).…”

“…In a p − bulk, faced on both surfaces by the usual very highly doped 2 n ++ and p ++ electrodes rendering the structure of the detector, an additional, highly doped p + layer (N A ≈ O(10 16 /cm 3 )) is implanted immediately underneath the n ++ 1 Typical noise values are on the order of 150 e − for the present LHC detectors [4,7] and will be around 80 e − for future detectors with smaller pixels [30]. 2 We here adopt the notation p ++ for N A 10 16 /cm 3 , likewise for n ++ . LGAD signal pulse detailing the contributions from electrons and holes before and after amplification following weighting field simulations [39].…”

Pixel detectors ... where do we stand?

“…For n-type material a practical and efficient mitigation has been invoked by oxygen enrichment having VO complexes competing with VP. For p-type material such an efficient cure still has to be established [24]. Therefore, while for LHC upgrades the change from p + − in − n to n + − in − p for LHC experiment upgrades is necessary for strip detectors, from the radiation point of view, n + − in − n (present pixel choice) is equally suited at least, except that for the fabrication of the latter double sided processing is needed.…”

A Comparison of the Effects of Neutron and Gamma Radiation in Silicon Photomultipliers

“…This mechanism, known as displacement damage, or the formation of Frenkel defects, Please see Acknowledgements for author affiliations. has been extensively studied and documented in the literature [20]- [23]. These defects can be either single point defects or cluster defects that can extend over distances of several hundred Angstroms in the lattice.…”