Linear response theory was used to predict threshold-voltage shifts for CC4007-NMOS device at dose rates of 0.1, 2.3, 44 and 91rad(Si)/s. These predictions were compared with the threshold-voltage shifts obtained after 60Co irradiations actually performed at these dose rates, and the agreement is excellent. Also, we use the linear response theory to predict the response of CC4007-NMOS device during radiation and 25℃ annealling for high and low-dose-rates. According to the predictions, under the same conditions of radiation and annealling, the threshold-voltage shifts caused by high dose-rate irradiation after room temperature annealling were equal to that by low-dose-rate irradiation within the limit of error, but the total times for both were the same. Finally, the failure doses for CC4007-NMOS device at different dose rates of irradiation were predicted also using the linear response theory.

In this paper the characteristics of isothermal and isochronal annealing for post-radiated MOS transistor were studied. The results show that 100℃ isothermal a nnealing is the most effective treatment, while the time of isochronal annealing is the shortest. Secondly, the recovery of threshold voltage under the +5V bias is the fastest and biggest, compared to that under 0V and float bias. These predictied results by using isochronal annealing data were compared with the ex periment curve obtained from isothermal annealing, and the agreement is good.

Ions with the same linear energy transfer (LET) value, but different energies and species have various ion track characteristics, and thus induce different single event transient (SET) responses in combinational logics. As the technology feature size shrinks, this issue continues to be serious. The research of the relationship between ion track characteristics and SETs in the nanometer combinational logic circuits is of great significance for accurately predicting the soft error rates of nanometer devices used in spacecraft. The combinational logic circuit investigated in this paper is a 65 nm bulk silicon complementary metal oxide semiconductor (CMOS) technology inverter chain. The three-dimensional TCAD model of the inverter chain is established, and the particle transport program for the ion track in bulk silicon is developed by Geant4. The track characteristics of high- and low-energy ions (the energy of low-energy ions is less than 10 MeV·n^–1, the energy of high-energy ions ranges from tens of MeV·n^–1 to hundreds of MeV·n^–1) which have the same LET value are compared with each other. Based on the coupled simulation of TCAD and Geant4, the difference in SET pulse widths, induced by ions with the same LET value but different energies, are investigated. It is found that when the energy per nucleon ratio of high-energy ion to low-energy ion increases, the difference in electron-hole pair densities near the center axis of the ion track is more significant, and thus the difference in SET pulse widths is larger. If the energy per nucleon ratio is similar, raising the LET value of ions can increase the difference in electron-hole pair densities on the same radial scale of the ion tracks, and make the SET pulse width difference more obvious. For the high- and low-energy ions with the same LET value, the single event charge generations are different. On the other hand, the change of the ion incident angle results in different charge collections. The coupling of these two factors makes the difference in SET pulse widths dependent on the incident angle of ions. In addition, the influence of ion track characteristics on SET has a weak correlation with the bias voltage of the inverter chain.

Ferroelectric random access memory (FeRAM) has superior features such as low power consumption, short write access time, low voltage, high tolerance to radiation. Data about the total ionizing dose (TID) radiation effects of FeRAM have not been rich in the literature so far. Experimental study of the ionizing radiation effect of FeRAM is carried out based on Co-60 γ rays and 2 MeV electrons. And the TID radiation damages to the FeRAM in the dynamic biased, static biased and unbiased case are studied. The direct current and alternating current parameters are tested by J-750. The test results indicate that the stored information about the memory cell has no change before failure, the ferroelectric capacitors are still able to hold the data. Accordingly, the TID failure of the FeRAM should be mainly ascribed to the poor TID hardness of the peripheral complementary metal oxide semiconductor circuits. Besides, three types of electric fields from three working conditions can result in different generation and recombination rates of electronhole pairs. For static biased case, the internal electric field in the FeRAM is constant. It can lead to high net production of the electronhole pairs and a great number of trapped charges. Hence the radiation damage in the static biased case is most serious. With the increase of the total radiation dose, the electrical parameters of FeRAM have different degradations. Part of the parameters that can be detected by J-750, may lapse before they are detected online. Standby current, operating power supply current, leakage current and output low voltage are radiationsensitive parameters of FeRAM through analyzing the test data. And, other parameters, which have slight changes, have small effect on the degradation of the device. Furthermore, the electron accelerator is used in electron irradiation experiment. By comparing the results of the two kinds of radiation tests, it is discovered that the electrons tend to cause lighter TID degradation than Co-60 γ rays because of the high density of electrons in the electron irradiation environment and low net production rate of electronhole pairs. In addition, the electrons have weaker penetration than Co-60 γ rays due to low energy. The device packaging, the upper metal layers can also influence the experimental result of electron irradiation. The above conclusions provide a reference value for the total dose effect of FeRAM and will be of great significance for studying the radiation hardening of FeRAM.

The experiments of ionizing radiation were performed on floating gate ROM device s by using 60Coγrays. The experimental aim was to examine the radi ation response at various dose rates. According to the extrapolation technique and the failu re criteria we defined,the parameter failure and function failure of devices vs. dose rate were studied. Finally, based on the function of failure timevs. doserate, the failure time of floating gate ROM device in space radiation environm ent was predicted.