Determination of radiation hardness of silicon diodes

In this paper, we describe an experiment aimed to measure the physical observables, which can be used for the assessment of the radiation hardness of commercially available silicon photo diodes commonly used as nuclear detectors in particle accelerator laboratories. The experiment adopted the methodology developed during the International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP No. F11016) “Utilization of Ion Accelerators for Studying and Modelling Ion Induced Radiation Defects in Semiconductors and Insulators”. This methodology is based on the selective irradiation of micrometer-sized regions with different fluences of MeV ions using an ion microbeam and on the measurement of the charge collection efficiency (CCE) degradation by Ion Beam Induced Charge (IBIC) microscopy performed in full depletion condition, using different probing ions. The IBIC results are analyzed through a theoretical approach based on the Shockley-Read-Hall model for the free carrier recombination in the presence of ion-induced deep traps. This interpretative model allows the evaluation of the material radiation hardness in terms of recombination parameters for both electrons and holes. The device under study in this experiment was a commercial p-i-n photodiode, which was initially characterized by i) standard electronic characterization techniques to determine its doping and ii) the Angle-Resolved IBIC to evaluate its effective entrance window. Nine regions of (100 × 100) µm2 were irradiated with 11.25 MeV He ions up to a maximum fluence of 3·1012 ions/cm2. The CCE degradation was measured by the IBIC technique using 11.25 MeV He and 1.4 MeV He as probing ions. The model presented here proved to be effective for fitting the experimental data. The fitting parameters correspond to the recombination coefficients, which are the key parameters for the characterization of the effects of radiation damage in semiconductors.</p

High-Speed Single-Event Current Transient Measurements in SiGe HBTs

Time-resolved ion beam induced charge reveals heavy ion response of IBM 5AM SiGe HBT: 1) Position correlation. 2) Unique response for different bias schemes. 3) Similarities to TPA pulsed-laser data. Heavy ion broad-beam transients provide more realistic device response: 1) Feedback using microbeam data 2) Overcome existing issues of LET and ion range with microbeam Both micro- and broad-beam data sets yield valuable input for TCAD simulations. Uncover detailed mechanisms for SiGe HBTs and other devices fabricated on lightly-doped substrates

Heavy Ion Microbeam- and Broadbeam-Induced Current Transients in SiGe HBTs

IBM 5AM SiGe HBT is device-under-test. High-speed measurement setup. Low-impedance current transient measurements. SNL, JYFL, GANIL. Microbeam to broadbeam position inference. Improvement to state-of-the-art. Microbeam (SNL) transients reveal position dependent heavy ion response, Unique response for different device regions Unique response for different bias schemes. Similarities to TPA pulsed-laser data. Broadbeam transients (JYFL and GANIL) provide realistic heavy ion response. Feedback using microbeam data. Overcome issues of LET and ion range with microbeam. **Angled Ar-40 data in full paper. Data sets yield first-order results, suitable for TCAD calibration feedback

Ion Beam Induced Charge Collection (IBICC) Studies of Cadmium Zinc Telluride (CZT) Radiation Detectors

Cadmium Zinc Telluride is an emerging material for room temperature radiation detectors. In order to optimize the performance of these detectors, it is important to determine how the electronic properties of CZT are related to the presence of impurities and defects that are introduced during the crystal growth and detector fabrication. At the Sandia microbeam facility IBICC and Time Resolved IBICC (TRIBICC) were used to image electronic properties of various CZT detectors. Two-dimensional areal maps of charge collection efficiency were deduced from the measurements. In order to determine radiation damage to the detectors, we measured the deterioration of the IBICC signal as the function of dose. A model to explain quantitatively the pattern observed in the charge collection efficiency maps of the damaged detectors has been developed and will be discussed in the paper

A review of ion beam induced charge microscopy

10.1016/j.nimb.2007.09.031Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms2642345-360NIMB

A new approach to nuclear microscopy: The ion-electron emission microscope

A new multidimensional high lateral resolution ion beam analysis technique, Ion-Electron Emission Microscopy or IEEM is described. Using MeV energy ions, IEEM is shown to be capable of Ion Beam Induced Charge Collection (IBICC) measurements in semiconductors. IEEM should also be capable of microscopically and multidimensionally mapping the surface and bulk composition of solids. As such, IIEM has nearly identical capabilities as traditional nuclear microprobe analysis, with the advantage that the ion beam does not have to be focused. The technique is based on determining the position where an individual ion enters the surface of the sample by projection secondary electron emission microscopy. The x-y origination point of a secondary electron, and hence the impact coordinates of the corresponding incident ion, is recorded with a position sensitive detector connected to a standard photoemission electron microscope (PEEM). These signals are then used to establish coincidence with IBICC, atomic, or nuclear reaction induced ion beam analysis signals simultaneously caused by the incident ion

Modeling of Heavy Ion Induced Charge Loss Mechanisms in Nanocrystal Memory Cell

We present the first charge loss model on nanocrystal memories the threshold voltage dependence on the ion hit number and position and it provides the estimation of the ion hit track size

Drain Current Decrease in MOSFETs After Heavy Ion Irradiation

In this work we are moving our attention on MOSFETs, which are the real basic element of all CMOS application. Our work presents a new degradation mechanism, which must not be confused with the single-event microdose effect presented by Oldham and McGarrity in 1981 [ref]. The incidence of a single ion can dramatically decrease the drain current capability of thin gate oxide MOSFET. This effects are emphasized by scaling down the transistor sizes. We think that neutral defect generation in those region corresponding to ion hits can be good candidate to explain these results, and we plan to extend the exploration of this new phenomenon that appears to be very interesting