The paradox of characteristics of silicon detectors operated at temperature close to liquid helium

Abstract

The aim of this study is to give characterization of silicon p+/n/n+ detectors for the monitoring systems of the Large Hadron Collider machine at CERN with the focus on justifying the choice of silicon resistivity for the detector operation at the temperature of 1.9–10 K. The detectors from n-type silicon with the resistivity of 10, 4.5, and 0.5 kΩ cm were investigated at the temperature from 293 up to 7 K by the Transient Current Technique with a 660 nm pulse laser and alpha-particles. The shapes of the detector current pulse response allowed revealing a paradox in the properties of shallow donors of phosphorus, i.e., native dopants in the n-type Si. There was no carrier freeze-out on the phosphorus energy levels in the space charge region (SCR), and they remained positively charged irrespective of temperature, thus limiting the depleted region depth. As for the base region of a partially depleted detector, the levels became neutral at T < 28 K, which transformed silicon to an insulator. The reduction of the activation energy for carrier emission in the detector SCR estimated in the scope of the Poole-Frenkel effect failed to account for the impact of the electric field on the properties of phosphorus levels. The absence of carrier freeze-out in the SCR justifies the choice of high resistivity silicon as the only proper material for detector operation in a fully depleted mode at extremely low temperature.

Position‐Sensitive Array Photodetector Based on Comb‐Like CdS Nanostructure with Cone‐Shape Branches

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Conceptual study of a two-layer silicon pixel detector to tag the passage of muons from cosmic sources through quantum processors

“…In the presence of doping profiles, carrier freezeout effects that occur at temperatures < 100 K become an important factor to control. Recent tests on non-irradiated 𝑝 + -𝑛-𝑛 + silicon sensors for possible high-luminosity LHC beam loss monitor designs [40] show only small differences in current pulses at temperatures between 100 K and 7.6 K for 4.5 and 10 kΩ cm silicon sensors with a bias voltage of 100 V (above depletion voltage). The pulse shapes at these temperatures are narrower as a function of time…”

Electric field distribution in Si detectors irradiated with 40Ar ions: experimental study and simulation

“…Thus, the time resolution of the TCT was limited mainly by the RC product of the installation (50 Ω input resistance of oscilloscope and the capacitance of the sample under study) and by the analog response of the coaxial cable line. The experimental setup was described in detail in [21].…”