L. Dusseau

Physical Model for the Low-Dose-Rate Effect in Bipolar Devices

A physical model of the dose-rate effect in bipolar junction transistors is proposed, based on competition between trapping and recombination of radiation-induced carriers in the oxide. The initial recombination of the carriers is considered in this model, taking into account the temperature effect. The general trends obtained with this model are in very good agreement with experimental data. It is also shown that the dose rate effect depends significantly on oxide quality

Estimation of low-dose-rate degradation on bipolar linear integrated circuits using switching experiments

The low-dose-rate response of five bipolar integrated circuits is evaluated on the basis of switching experiments. Such experiments consist of performing first a high-dose-rate irradiation followed by a low-dose-rate irradiation. Based on these experiments, a time-saving method to predict the low-dose-rate degradation of bipolar linear microcircuits is proposed. This approach provides a good estimate of the low-dose-rate degradation.

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.

The Effects of Low Dose-Rate Ionizing Radiation on the Shapes of Transients in the L>M124 Operational Amplifier

Shapes of single event transients (SETs) in a linear bipolar circuit (LM124) change with exposure to total ionizing dose (TID) radiation. SETs shape changes are a direct consequence of TID-induced degradation of bipolar transistor gain. A reduction in transistor gain causes a reduction in the drive current of the current sources in the circuit, and it is the lower drive current that most affects the shapes of large amplitude SETs.

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.

Impact of Total Ionizing Dose on the Analog Single Event Transient Sensitivity of a Linear Bipolar Integrated Circuit

Total ionizing dose (TID) strongly affects the single event transient (SET) sensitivity of a bipolar linear voltage comparator (LM139). The general rule that transistors in the non-conducting state are the most sensitive to SETs was verified, with some exceptions. The mechanisms responsible for those exceptions were identified and explained using circuit analysis. In the non typical behavior, a correlation of the degradation of the amplifier stages with the shape of the transient output signal was established. Following total dose exposure the SETs generally exhibit a reduction in amplitude due to the degradation of the slew rate. However, in some cases the transient signal is amplified because degradation of either the current source or of the current gain of some transistors forces the output transistor to the edge of conduction, so that it behaves like a voltage amplifier and amplifies the parasitic transient signal. Laser testing demonstrates that ASET sensitivity also is affected by TID degradation of transistors that are not directly hit by the laser.

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.

The Use of a Dose-Rate Switching Technique to Characterize Bipolar Devices

The enhanced radiation sensitivity exhibited at low dose rate by many bipolar devices remains one of the main concerns for spacecraft reliability. As an accelerated test technique, a new approach based on dose-rate switching experiments has been proposed to characterize bipolar devices. The foundations of this approach are detailed and guidelines for its use are given.

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.