Radiation hardness of amorphous silicon particle sensors

Abstract

Radiation tests of 32 lm thick hydrogenated amorphous silicon n-i-p diodes have been performed using a high-energy 24 GeV proton beam up to fluences of 2 · 10 16 protons/cm 2 . The results are compared to irradiation of similar 1 lm and 32 lm thick n-i-p diodes using a proton beam of 405 keV at a fluence of 3 · 10 13 protons/cm 2 . All samples exhibited a drop of the photoconductivity and an increase in the dark leakage current under both high-and low-energy proton irradiation. An almost full recovery of the device performance was observed after a subsequent thermal annealing.

Review of amorphous silicon based particle detectors: the quest for single particle detection

“…32-µm-thick a-Si:H diodes were exposed to a 24 GeV proton beam in the "IRRAD1" facility up to fluences of 2×10 16 protons/cm 2 [70]. Figure 6 shows the current induced by the proton spills (120-ms-long periods of "beam on" with an average fluence of 1.3×10 11 protons).…”

High Spatial Resolution of Thin-Film-on-ASIC Particle Detectors

“…Nevertheless, the mid-gap defects in a-Si:H are metastable which means that their concentration can be brought back to pre-degradation values by annealing at temperatures up to the deposition temperature ( ) [19], [22]. The "aSiHtest" detector with the 10 thick intrinsic layer, which absorbed a dose of about 17.6 MGy (in 2250 ) for each sweep, recovered 70% of its initial signal-to-noise ratio after 70 hours of annealing at 130 .…”

“…This fluence corresponds to five years of operation of the future Super LHC (SLHC) and explains the presence of a-Si:H on a list of candidate materials for SHLC next-generation detectors [4]. A larger degradation is observed when irradiating with charged particles of low and medium energies (tens to hundreds of keV) as all of their energy is transferred to the material [19]- [22]. This is the case for the measurements with the electron beam presented in this paper.…”

“…Its disordered structure and hydrogen content (10%-20%), used to passivate electronic defects and limit degradation of the material properties. As an example, a-Si:H-based detectors were demonstrated to retain reasonable performance (a loss of only 50% in the proton-induced current) after irradiation with a 24 GeV proton beam with a fluence of up to [19]. This fluence corresponds to five years of operation of the future Super LHC (SLHC) and explains the presence of a-Si:H on a list of candidate materials for SHLC next-generation detectors [4].…”

An amorphous silicon photodiode array for glass-based optical MEMS application

“…The deposited photodiodes were realized in hydrogenated amorphous silicon (a-Si:H). It is an alloy of silicon with around 10% (atomic) hydrogen and offers several significant advantages; low deposition temperature (around 200°C), high resistance to radiation [25], and mechanical properties close to c-Si. Being issued from the solar cell research, they show excellent characteristics in terms of quantum efficiency (as high as 80% between 500 and 600 nm), low dark current (1e-10 A/cm 2 for -3V polarization) [26].…”