Studies of radiation hardness of oxygen enriched silicon detectors

Abstract

Detectors of high-energy particles sustain substantial structural defects induced by the particles during the operation period. Some of the defects have been found to be electrically active, degrading the detector's performance. Understanding the mechanisms of the electrical activities and learning to suppress their influence are essential if long 'lifetime' detectors are required. This work reports about radiation hardness of silicon P-I-N devices fabricated from oxygen-enriched, high-resistivity material. The high and nearly uniform concentration of oxygen in float-zone silicon has been achieved by diffusion of oxygen from SiO 2 layers.

Trapping of Electrons and Holes in p-type Silicon Irradiated with Neutrons

“…Oxygenation with diffusion does not improve radiation hardness for neutrons. Same has been previously observed after neutron irradiation of oxygenated and non-oxygenated n-type FZ silicon [12]. The average value of the acceptor creation rate is g = 2.0 10 -2 cm -1 .…”

Radiation hardness of oxygenated microstrip detectors read out with LHC speed electronics

“…The broad conclusions found for the full-sized and miniature detectors are supported in terms of the extent of the benefits coming from oxygenation regarding the bias voltages needed for near maximum charge collection. The depletion voltages derived using the CV technique for these devices (quoted in the figures) are in good agreement with other published results [3], [5], as is shown in Fig. 8.…”

“…(Here the diodes were irradiated at room temperature without bias and the capacitance values have been measured at 10 kHz.) Not only do these figures confirm the results reported elsewhere [3], [5], [8] that oxygenation significantly reduces the changes in the bulk effective doping concentration with fluence, but they also show that the simpler diffusion from field oxide technique is as effective as the more complicated and, therefore, more costly ion implantation approach. The measurements are for diodes that have been annealed at each fluence step for 4 min at 80 C to bring them to the minimum of the characteristic annealing curve [3], [5].…”

“…It is particularly in this range of voltages 2 Upton, NY. 3 Warsaw, Poland. that most of the operational advantages of using oxygenated devices are lost.…”

Improving the radiation hardness properties of silicon detectors using oxygenated n-type and p-type silicon

“…They were irradiated in successive steps of fluence and measured (capacitance vs bias, CV, and reverse current vs bias, IV) after each step. Before any measurement the diodes were heated at 80 o C for 4 minutes, in order to complete the beneficial annealing [10] stage and minimise the variation with time of the CV and IV characteristics. where ε Si is the permittivity of silicon, e is the electron charge and w is the detector thickness.…”