J. Gasiot

Determination of key parameters for SEU occurrence using 3-D full cell SRAM simulations

A 3-D entire SRAM cell, based on a 0.35-/spl mu/m current CMOS technology, is simulated in this work with a DEVICE simulator. The transient current, resulting from a heavy ion strike in the most sensitive region of the cell, is studied as a function of the LET value, the cell layout and the ion penetration depth. A definition of the critical charge is proposed and two new methods are presented to compute this basic amount of charge only using SPICE simulations. Numerical applications are performed with two different generations of submicron CMOS technologies, including the determination of the sensitive thicknesses.

SEU critical charge and sensitive area in a submicron CMOS technology

This work presents SEU phenomena in advanced SRAM memory cells. Using mixed-mode simulation, the effects of scaling on the notions of sensitive area and critical charge is shown. Specifically, we quantify the influence of parasitic bipolar action in cells fabricated in a submicron technology.

Evidence of the ion's impact position effect on SEB in N-channel power MOSFETs

Triggering of Single Event Burnout (SEB) in Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) is studied by means of experiments and simulations based on real structures. Conditions for destructive and nondestructive events are investigated through current duration observations. The effect of the ions impact position is experimentally pointed out. Finally, further investigation with 2D MEDICI simulations show that the different regions of the MOSFET cell indeed exhibit different sensitivity with respect to burnout triggering. >

A new approach for the prediction of the neutron-induced SEU rate

A new approach for SEU rate prediction in components submitted to neutron environment is presented. The method aims to take into account the characteristics of the secondary particles in terms of electrical effect. So, in addition to the critical energy/charge criterion generally used until now, two criteria are tentatively proposed : a critical LET and a limited distance in which energy must be deposited. The starting point of each computation is a common neutron-silicon interaction database.

Experimental and 2D simulation study of the single-event burnout in N-channel power MOSFETs

The use of the 2D simulator MEDICI as a tool for single event burnout (SEB) comprehension is investigated. Simulation results are compared to experimental currents induced in an N channel power MOSFET by the ions from a /sup 252/Cf source. Current measurements have been carried out using a specially designed circuit. Simulations make it possible to analyze separately the effects of the ion impact and the electrical environment parameters on the SEB phenomenon. Burnout sensitivity is found to be increased by increasing supply voltage and ion linear energy transfer (LET), and by decreasing load charge. These electrical tendencies are confirmed by experiments. Burnout sensitivity is also found to be sensitive to the ion impact position. The current shape variations for given electrical parameters can be related to LET or ion impact position changes. However, some experimental current shapes are not reproduced by simulations. >

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.

Hafnium and Uranium Contributions to Soft Error Rate at Ground Level

Current technologies are sensitive to low Linear Energy Transfer particles such as alphas. These particles can be spontaneously produced by some radioactive elements, called alpha-emitters. Here, we investigate two examples of emitters, Hafnium and Uranium. By calculating the disintegration rate in a modern technology with hafnium dioxide, we show that hafnium has no incidence on Soft Error Rate. Moreover, from Monte Carlo simulations, we point out that natural Uranium concentration in a silicon wafer lead to a Soft Error Rate comparable to that due to neutrons at ground level.

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.