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Silicon particle detectors made on Czochralski and float zone silicon materials were irradiated with 7 and 9 MeV protons at a temperature of 220 K. During the irradiations, the detectors were biased up to their operating voltage. Specific values for the fluence and flux of the irradiation were found to cause a sudden breakdown in the detectors. We studied the limits of the fluence and the flux in the breakdown as well as the behavior of the detector response function under high flux irradiations. The breakdown was shown to be an edge effect. Additionally, the buildup of an oxide charge is suggested to lead to an increased localized electric field, which in turn triggers a charge carrier multiplication. Furthermore, we studied the influences of the type of silicon material and the configuration of the detector guard rings. [ABSTRACT FROM AUTHOR]

Diffusion of Ga in relaxed intrinsic Si1-xGex layers has been determined at 907 °C within the whole composition range. Based on current results and available systematic diffusion data for Si, Ge, and Si1-xGex alloys, it is suggested that Ga diffusion is interstitialcy mediated in Si rich materials and vacancy mediated in Ge rich materials. The results indicate that the dominating diffusion mechanism change takes place at x∼0.6. [ABSTRACT FROM AUTHOR]

Effect of silicon doping on the elastic–plastic transition of GaAs crystal is demonstrated by results of nanoindentations and ab initio simulations. The experiments show that an increase of silicon concentration causes a decrease of the contact pressure at the onset of permanent deformation of GaAs nanovolume. We found the substitutional Si point defects to decrease the pressure of GaAs-I → GaAs-II phase transformation, which proves the elastic–plastic transition of Si-doped GaAs crystal is a phase-change-driven phenomenon. [ABSTRACT FROM AUTHOR]

A hybrid Coulomb blockade thermometer (CBT) in form of an array of intermittent aluminum and silicon islands connected in series via tunnel junctions was fabricated on a thin silicon-on-insulator (SOI) film. Tunnel barriers in the micrometer size junctions were formed by metal-semiconductor Schottky contacts between aluminium electrodes and heavily doped silicon. Differential conductance through the array vs. bias voltage was found to exhibit characteristic features of competing thermal and charging effects enabling absolute temperature measurements over the range of ~65 to ~500mK. The CBT performance implying the primary nature of the thermometer demonstrated for rather trivial architecture attempted in this work paves a route for introduction of Coulomb blockade thermometry into well-developed contemporary SOI technology. [ABSTRACT FROM AUTHOR]

The time evolution of the silicon concentration profiles in ion-implanted polycrystalline α-Ti has been studied in the temperature range 650–800 °C. Diffusion couples were created by ion implantation. The time-dependent concentration profiles were monitored by the use of the nuclear resonance broadening technique through the 30Si(p,γ)31P reaction. The values of 1.09±0.18 eV for the activation energy and (4.4±404.0)×10-7 cm2/s for the frequency factor were obtained. The solubilities of Si in Ti are reported. The present result is discussed in the framework of the Ti silicide formation. [ABSTRACT FROM AUTHOR]

Abstract: The influence of an electrical field on the formation of defects in silicon particle detectors during particle irradiation was studied. Silicon pad detectors processed on Float Zone and Magnetic Czochralski silicon were irradiated with 7-MeV protons between the fluences of 5×1012 and 1.25×1013 protons/cm2. The irradiations were performed at 220K, with half of the samples being kept under reverse bias voltage. The full depletion voltage of the detectors was extracted by capacitance–voltage (CV) measurements immediately after the irradiations. The samples were re-measured for CV and current–voltage (IV) characteristics after a 26-day storage period at 255K and again after a further storage period of about two months at 273K. The samples were finally studied by means of the transient current technique (TCT) with infrared (1060nm) and red (670nm) lasers. An explicit conclusion of the study is that the irradiation of the detectors with a simultaneously applied bias voltage reduces the introduction of the negative space charge and the current-related damage for both detector types. [Copyright &y& Elsevier]