J. Fesquet

Prediction of low dose-rate effects in power metal oxide semiconductor field effect transistors based on isochronal annealing measurements

A method for predicting the long term behavior of semiconductor devices in the low dose-rate ionizing-radiation space environment is presented. The operating conditions related to this environment are briefly reviewed. The new method consists of three major steps. The first step is the determination of the trap characteristics using the experimental recording of an isochronal annealing curve. The second step is the prediction of the isothermal annealing behavior deduced from the experimentally deduced trap characteristics. This approach makes it possible to avoid time-consuming isothermal measurements. As trapping and detrapping processes are independent, combining both processes by convolution, the last step, allows prediction of low dose-rate effects. Up to now, this accelerated characterization method has not been applied to electronic devices. An experimental application of the model to predict the long term behavior of a typical metal oxide semiconductor field effect transistor is given and the resul...

Experimental validation of an accelerated method of oxide-trap-level characterization for predicting long term thermal effects in metal oxide semiconductor devices

A new method for accelerated prediction of the long-term thermal annealing of bulk oxide trapped charge in the low dose rate space environment was presented in a previous paper. This method, based on the thermal detrapping characteristics is briefly reviewed. From a single experimental isochronal curve, the long term isothermal behavior of the device is predicted and compared with an experimental isothermal curve. Four different devices, obtained from four different manufacturers, were examined to demonstrate the validity of this method. In all four cases, the predicted long-term thermal behavior is in good agreement with experimental results. This methods application is discussed for space missions.

Effect of switching from high to low dose rate on linear bipolar technology radiation response

The degradation of discrete and integrated-circuit bipolar technologies irradiated at High Dose Rate (HDR) and then switched to Low Dose Rates (LDR) is studied. It is shown that the degradation rate of switched devices is equal to that found at low dose rates for all the tested devices.

An integrated sensor using optically stimulated luminescence for in-flight dosimetry

The feasibility of an integrated sensor based on Optically Stimulated Luminescence (OSL) dosimetry is demonstrated. The principle and the basic structure are reviewed. A lab demonstrator was realized and a board designed to operate the sensor at different doses and doses rates. The first calibrations are presented and discussed.

Quality control of intensity modulated radiation therapy with optically stimulated luminescent films

An optically stimulated luminescent (OSL) dose mapping system is characterized and its possible application to intensity modulated radiotherapy therapy (IMRT) treatment investigated. The dose map obtained during an IMRT treatment performed on a Plexiglas phantom corroborates the results obtained with radiological films.

Characterization of an integrated sensor using optically stimulated luminescence for in-flight dosimetry

The signal linearity versus a dose of an integrated sensor based on optically stimulated luminescence is examined with electrons, protons, and photons of various energies. This new kind of space dosimeter is an integrator erased by the dose measurement. Thus, it allows the detection of small doses (1 mGy) with the exploitation of its whole dynamic (4 decades) at each measurement.

Experimental determination of the frequency factor of thermal annealing processes in metal–oxide–semiconductor gate-oxide structures

Radiation-induced trapped charge annealing processes in the gate and field oxides of metal–oxide–semiconductor field-effect transistors are thermally activated. The activation energy and the frequency factor are related to the relaxation time constant by an Arrhenius law. A simple measurement of the relaxation time constant defines the activation energy, frequency factor (E,ν) pair. Choosing arbitrarily a “realistic” frequency factor corresponds to determining a characteristic energy, on which depends any subsequent annealing prediction. A controversy exists about the appropriate value of ν for silicon dioxide, with published values ranging from 1×107 to 1×1014 s−1. In this paper, a new method is presented that yields values for both frequency factor and activation energy. This method leads to an unexpectedly low (but consistent) value of ν (about 1×107 s−1) when applied to three different devices, obtained from three different manufacturers. The experimental procedure and the results for all three cases ...

High energy electron dose-mapping using optically stimulated luminescent films

High energy electron dose mapping is a complex subject. Experiments using optically stimulated luminescent films behind various shielding structures and dual inline packages are presented. The dose-depth deposition in an epoxy package is also investigated. These results are compared with PENELOPE transport code calculations.

Irradiated integrated circuits dose-attenuation mapping using optically stimulated phosphors for packaging dosimetry

The feasibility of a dose mapping system using optically stimulated luminescent (OSL) phosphors is demonstrated. The OSL technique is briefly reviewed as well as its interest for calculation code calibration. The sensors and the reading apparatus are presented. An example of attenuation dose map obtained for a dual in line plastic package (DIL) is given and the results compared to calculations with the code EGS4 PRESTA. Results obtained by experiment and simulation are discussed as well as the potentialities of the method.

High-energy particle irradiation of optically stimulated luminescent films at CERN

For the first time, optically stimulated luminescent (OSL) dosimeters have been irradiated at CERN with high-energy particles. Two experiments with existing OSL films are presented: measuring the dose delivered by 3.66-GeV negative pions and mapping the intensity profile of a 23-GeV proton beam. An on-line dosimeter is also presented and applied to the monitoring of the dose delivered by a 500-MeV electron beam. The results are discussed with regards to the specific concerns raised by high doses and high energies.