D. Pantano

SIRAD: an irradiation facility at the LNL Tandem accelerator for radiation damage studies on semiconductor detectors and electronic devices and systems

This article describes the essential features of the SIRADfacility of the INFN Laboratori Nazionali di Legnaro. This facility, located at the 15 MV Tandem accelerator, is dedicated to radiation damage studies (bulk damage, total dose and Single Event Effects) induced by protons and heavy ions on semiconductor detectors, electronic devices and systems. SIRADis at present routinely used by groups involved in detector development for elementary particle physics, in electronic device physics and in space applications. # 2001 Elsevier Science B.V. All rights reserved.

MRS detectors with high gain for registration of weak visible and UV light fluxes

Abstract Operation of silicon avalanche detectors based on a Metal-Resistive layer-Semiconductor (MRS) structure is presented. Results refer to a new batch of detectors fabricated on a n-type substrate especially made to be used as light detecting elements of a scintillating fiber detector for high energy physics applications. These detectors are meant for weak light fluxes in the range 200–600 nm (called UV MRS). Measurements of gain, noise and quantum efficiency were performed and operation of the detector at different temperatures was also studied.

Radiation damage of standard and oxygenated silicon diodes irradiated by 16-MeV and 27-MeV protons

The effects of irradiation by 16- and 27-MeV protons on standard and oxygenated silicon diodes, processed by different technologies, have been investigated. The acceptor creation rate /spl beta/ can be lower for standard diodes than for state-of-the art oxygenated devices, suggesting that the role of oxygen is more complex than expected and must be folded with the technology of the fabrication process. In addition, we show the inaccuracy of the /spl beta/ normalization by the nonionizing energy loss factor not only for oxygenated diodes but also for standard nonoxygenated devices.

Monolithic active pixel sensor development for the upgrade of the ALICE inner tracking system

ALICE plans an upgrade of its Inner Tracking System for 2018. The development of a monolithic active pixel sensor for this upgrade is described. The TowerJazz 180 nm CMOS imaging sensor process has been chosen as it is possible to use full CMOS in the pixel due to the offering of a deep pwell and also to use different starting materials. The ALPIDE development is an alternative to approaches based on a rolling shutter architecture, and aims to reduce power consumption and integration time by an order of magnitude below the ALICE specifications, which would be quite beneficial in terms of material budget and background. The approach is based on an in-pixel binary front-end combined with a hit-driven architecture. Several prototypes have already been designed, submitted for fabrication and some of them tested with X-ray sources and particles in a beam. Analog power consumption has been limited by optimizing the Q/C of the sensor using Explorer chips. Promising but preliminary first results have also been obtained with a prototype ALPIDE. Radiation tolerance up to the ALICE requirements has also been verified.

Investigating Degradation Mechanisms in 130 nm and 90 nm Commercial CMOS Technologies Under Extreme Radiation Conditions

The purpose of this paper is to study the mechanisms underlying performance degradation in 130 nm and 90 nm commercial CMOS technologies exposed to high doses of ionizing radiation. The investigation has been mainly focused on their noise properties in view of applications to the design of low-noise, low-power analog circuits to be operated in harsh environment. Experimental data support the hypothesis that charge trapping in shallow trench isolation (STI), besides degrading the static characteristics of interdigitated NMOS transistors, also affects their noise performances in a substantial fashion. The model discussed in this paper, presented in a previous work focused on CMOS devices irradiated with a 10 Mrad(SiO2) gamma -ray dose, has been applied here also to transistors exposed to much higher (up to 100 Mrad(SiO2 )) doses of X-rays. Such a model is able to account for the extent of the observed noise degradation as a function of the device polarity, dimensions and operating point.

Low- and high-energy proton irradiations of standard and oxygenated silicon diodes

Oxygenated and standard (not oxygenated) silicon diodes processed by two different manufacturers (ST Microelectronics and Micron Semiconductor) have been irradiated by low (27 MeV) and high- (24 GeV) energy protons. The leakage current density increase rate (/spl alpha/) and its annealing do not show any significant dependence on oxygenation and are the same for both manufacturers. Oxygenation improves the radiation hardness by decreasing the acceptor introduction rate (/spl beta/) and mitigating the depletion voltage (V/sub dep/) increase. Nevertheless, standard ST diodes present /spl beta/ values lower than Micron standard devices and close to oxygenated devices, whose /spl beta/s are similar for both manufacturers. The amplitude of the V/sub dep/ reverse annealing is reduced by oxygenation, which in addition delays the electrically active defect increase, at least for high-energy protons. Oxygenation is consequently the best approach for silicon substrate radiation hardening.

Metal-Resistive layer-Silicon (MRS) avalanche detectors with negative feedback

Abstract The main electrical characteristics at room temperature of metal-resistive layer-semiconductor avalanche detectors are presented for devices with a Ti/SiC/p-Si structure. The device response has been tested by using a 90 Sr source. The consequences on the device behavior induced by substrate inhomogeneities have been modeled, and compared with those occurring in conventional Avalanche Photo Diodes (APD).

Radiation damage of oxygenated silicon diodes by 27 MeV protons

SummaryThe radiation damage induced by 27 MeV protons has been studied on diodes fabricated from standard and oxygen-enriched FZ substrates. Measurements confirm that the damage constant α is insensitive to the oxygen concentration whereas the acceptor creation rate parameter β is lower for oxygenated diodes. However, the effect is significantly smaller than that observed with high-energy protons, but somewhat higher than that by reactor neutrons. Data have been collected at the irradiation facility of the Tandem at the INFN Laboratories of Legnaro.

Ion electron emission microscopy at the SIRAD single event effect facility

The SIRAD facility at the 15 MV Tandem accelerator of the INFN Legnaro Laboratory is dedicated to characterizing the global sensitivity of electronic devices and systems to single event effects (SEE) due to ion impacts over a wide range of linear energy transfer. To map out device sensitivity with micrometric resolution, an ion electron emission microscope will be used to localize the impact point of each ion, with spatial resolution better than 1 μm, by imaging the secondary electrons emitted by the device. A fast position sensitive detector will handle rates >104 Hz. The system will be fully ion-impact reconstruction efficient for ions with Z⩾8.

Neutron irradiation effects on standard and oxygenated silicon diodes

Silicon diodes processed on standard and oxygenated silicon substrates by two different manufacturers have been irradiated by neutrons in a nuclear reactor and by the /sup 9/Be(d,n)/sup 10/B nuclear reaction. The leakage current density (J/sub D/) increase is linear with the neutron fluence. J/sub D/ and its annealing curve at 80/spl deg/C do not present any sizeable dependence on substrate oxygenation and/or manufacturing process. On the contrary, standard devices from one manufacturer present the lowest acceptor introduction rate (/spl beta/) for the effective substrate doping concentration (N/sub eff/), showing that the /spl beta/ dependence on the particular process can be important, overtaking the small substrate oxygenation effect. Finally, the average saturation value of the N/sub eff/ reverse annealing is slightly lower for the oxygenated samples, pointing out a positive effect of the substrate oxygenation even for devices irradiated by neutrons.