A comprehensive analysis of low-resistivity silicon radiation detectors

Abstract

Low-resistivity materials have been proposed for the fabrication of radiation-hard solid-state particle detectors. A complete analysis of low-resistivity detector performance, including the estimate of charge collection efficiency, has been carried out by using a numerical device simulator, and compared with results expected from conventional, high-resistivity devices. By exploiting the features of the CAD environment, characterization of devices over a wide range of fluences and applied biases has been possible, avoiding the actual fabrication of prototypes, as well as lengthy and expensive testing procedures. Encouraging results have been obtained: low-resistivity devices appear to provide some definite advantages in terms of long-term performance optimization.

Characterization of neutron irradiated, low-resistivity silicon detectors

“…A confirmation of these theoretical suppositions was given both by results on small diodes [1] and by computer simulations [2].…”

“…As mentioned before these measurements were affected by the error on the fluence; moreover, in our experimental set-up we were not able to distinguish the contribution of the surface current, gathered by the guard ring, from the total current and this might result in an overestimate of the α parameter. Previous simulation work [2] had pointed out that no difference would have been expected in the leakage current of LR and HR detectors once the full depletion voltage had been reached. Our results on diode currents show a slightly smaller α for the LR substrate, and roughly the same I − V characteristics for the detectors.…”

“…According with these preliminary results, as well as with previously related work (e.g. [2], and works therein referenced), a complete experimental characterization of low resistivity detectors has been carried out.…”

“…In particular, in order to predict devices performance before their actual fabrication, the general-purpose device simulator HFIELDS, suitably modified to account for radiation-related effects [2], has been exploited. Different DC-and AC-analyses have been carried out, aiming at evaluating the main parameters of irradiated detectors (e.g.…”

“…The damage effect was modelled at a physical level accounting for "deep-level" radiation-induced recombination centers, described by means of a generalized Shockley-Read-Hall statistics [2]. In particular, according to the main experimental findings [3], two deep levels were considered, the dominant "acceptor" level being related to the divacancy VV(-/0) complex, and the dominant "donor" level to the C i O i complex.…”