Radiation effects in silicon detectors processed on carbon and oxygen-rich substrates

Silicon detectors with a three-dimensional architecture, in which the n-and p-electrodes penetrate through the entire substrate, have been successfully fabricated. The electrodes can be separated from each other by distances that are less than the substrate thickness, allowing short collection paths, low depletion voltages, and large current signals from rapid charge collection. While no special hardening steps were taken in this initial fabrication run, these features of three-dimensional architectures produce an intrinsic resistance to the effects of radiation damage. Some performance measurements are given for detectors that are fully depleted and working after exposures to proton beams with doses equivalent to that from slightly more than ten years at the B-layer radius (50 mm) in the planned Atlas detector at the Large Hadron Collider at CERN.

Section: Introductionmentioning

confidence: 91%

Performance of 3-D architecture silicon sensors after intense proton irradiation

Parker

Kenney

2001

“…In this way, a high oxygen concentration detector can be processed with low thermal budget, i.e., high-temperature long time (HTLT) diffusion oxygenation process [1]- [3] is not needed. It is remarkable that the pre-irradiation of TD compensated detectors is well below the 300 V typical for 300 m thick n-type Cz-Si detectors [5], [7].…”

Section: Discussionmentioning

confidence: 99%

“…These lead to increased leakage currents and elevated depletion voltages. Deliberate introduction of oxygen into the silicon material has been experimentally proven to alter the formation of electrically active radiation induced defect centers and, thus, improves the electrical properties of silicon detectors used in harsh radiation environments [1]- [3]. The sensors used in particle tracking systems must be fully depleted at reasonably low operating voltages, typically less than 100 V. Therefore, the silicon sensors have traditionally been fabricated on wafers made by the float zone (Fz-Si) crystal growth technique.…”

Section: Introductionmentioning

confidence: 99%

p/sup +//n/sup -//n/sup +/ cz-Si detectors processed on p-type boron-doped substrates with thermal donor induced space charge sign inversion

Härkönen

Tuovinen

Luukka

et al. 2005

We have processed pad detectors on high-resistivity p-type Cz-Si wafers. The resistivity of the boron-doped silicon is approximately 1.8 k cm after the crystal growth. The detector processing was carried out using the common procedure for standard n-type wafers, to produce p + p p n + detector structures. During the last process step, i.e., sintering of aluminum electrode, the p-type bulk was turned to n-type through generation of thermal donors (TD). This way, high oxygen concentration p + n + Cz-Si detectors were realized with low temperature process. The full depletion voltage of detectors could be tailored between wide range from 30 V up to close 1000 V by changing heat treatment at 400 C-450 C duration from 20 to 80 min. The space charge sign inversion (SCSI) in the TD generated devices (from p + p n + to p + n (inverted) n + ) has been verified by transient current technique measurements. The detectors show very small increase of full depletion voltage after irradiations with 24 GeV/c protons up to 5 10 14 p/cm 2 .

“…Results on large-area 6 6 cm and miniature detectors 1 1 cm have been obtained with the SCT128 [1] 25-ns analog Large Hadron Collider (LHC) readout electronics and with a single-channel Phillips Scientific Model 6954 amplifier. In both cases, the signal after irradiation for oxygenated detectors rises faster with voltage than for nonoxygenated detectors, but the voltages at which the charge collection efficiency (CCE) starts to saturate only differ by at most 50 V. Such differences in saturation voltage are lower than would have been anticipated on the basis of the earlier capacitance-voltage (CV)-derived depletion voltage studies with irradiated oxygenated and Many studies have been performed with oxygenated and nonoxygenated diodes that confirm that with oxygen diffused into the high-purity silicon substrate at concentrations 10 cm , the radiation hardness to charged hadrons is much improved in terms of the changes in the effective doping concentration with fluence [2], [4], [5]. This has raised hopes that using oxygenated silicon substrates for the production of detectors will lead to devices better able to withstand the very high radiation levels anticipated at the LHC [6], [7].…”

Section: Introductionmentioning

confidence: 91%

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

Allport

Booth

Bowcock

et al. 2001

Full-size and miniature Large Hadron Collider (LHC) detectors fabricated on 4-and 6-in wafers have been processed using oxygenated and nonoxygenated substrates. After irradiation to 3 10 14 cm 2 with 24-GeV/c protons and short-term annealing, these detectors have been studied in terms of their charge collection as a function of depletion voltage with LHC-speed analog electronics. Results are presented indicating the degree of improvement seen in terms of the main operationally significant parameter, namely, the bias voltage needed for a given signal read out with fast electronics.