Basic mechanisms of SET effects in bipolar transistors fabricated by epitaxial planar and SOI technologies were investigated in wide temperature range. Obtained results can be useful for developing of models for circuit simulations of SEE effects in bipolar devices.

Physical model, which describe temperature dependence of surface recombination current in bipolar transistors, was proposed and experimentally verified. The model can be used for numerical estimation of temperature drift of electrical parameters of bipolar devices at different total dose levels.

We have estimated various types of errors dosimeters based on n-channel field-effect transistors with a metal-insulator-semiconductor structure (called as RADFETs). The radiation sensitivity have been experimentally investigated. There were measured the gate voltage of RADFET -based dosimeter as function of total ionizing dose (TID) at constant values of the drain current and the drain - source voltage, as well as the current -voltage characteristics before and after irradiations at different TID. We showed how radiation sensitivity and errors of sensors are depending on TID and electrical modes. Electro-physical models were proposed to interpret obtained results.

Influence of temperature and electrical modes on sensitivity and errors of ionizing radiation dose senor based on n- MOSFET (called as RADFET) have been investigated. There were measured the circuit's output voltages being equal to the gate voltage of RADFET-based dosimeter as function of the radiation doses at const values of the drain current and the drain - source voltage (conversion functions), as well as the current - voltage characteristics before, during and after irradiations at different temperatures. We showed how conversion functions, radiation sensitivities and errors are depending on the temperature and electrical modes. It is found that the conversion functions) have two characteristic regions for low and high doses (with negative and with positive radiation sensitivities). To interpret experimental data there were proposed the models of conversion function, its components and errors taking into account the separate contributions of charges in the dielectric and in SiO 2 -Si interface. Proposed models interpreting the experimental data can be used to predict performances of RADFET-based dosimeters.

We investigated the possibilities of using field-effect transistors to measure the dose rate of ionizing radiation using the example of an n-channel MOSFET. There were measured the gate voltage of transistors as function of ionizing dose at const values of the drain current and the drain-source voltage for different dose rates, as well as the current-voltage characteristics before and after irradiations. On the basis of the proposed models, the sensitivity, errors, and range of radiation dose rate measurement are estimated.

Dependences of LM 111 voltage comparator input current on time during post-radiation annealing are investigated. The technique based on the Gummel- Poon model of a bipolar transistor for numerical simulation of the annealing process, taking into account the temperature drift of the radiation-sensitive parameter is presented.

A possible influence of location of the effective Fermi level in the forbidden gap of the surface base region on dose rate sensitivity of bipolar integrated circuits was described. Also, it is shown, that the position of the effective Fermi level leads to different behavior of bipolar devices during post-irradiation annealing at enhanced temperature. Experimental tests on dose rate sensitive devices were provided and discussed.

The performance of the total ionizing dose sensor based on a bipolar transistor were researched in this work.

Modification of the ELDRS (Enhanced Low Dose Rate Sensitivity) conversion model is presented. The effect of the oxide trapped charge on the value of the oxide electric field and the yield of the oxide charge takes into account. It leads to dependence of the accumulation of radiation-induced oxide charge and interface traps on the dose rate. In enhancement version the ELDRS conversion model describes the low dose rate effect as “true” dose rate effect.

Real time dependence of operation temperature, which is typical for space environment, was taken into account in the numerical simulation of radiation degradation of LM111 bipolar voltage comparator input current. The technique and results of performed numerical analyses are presented and discussed.

The application of elevated temperature irradiation for simulating of low dose rate degradation in bipolar devices was considered. The analysis was performed in the framework of the conversion model, which enables to estimate the radiation degradation at any dose rate, temperature and total dose numerically. The possibility of application of the conversion model for the numerical estimation of radiation-induced increase of LM111 input current under low dose rate radiation impact was demonstrated experimentally. A test method using four-stage elevated single temperature irradiation was proposed. The ability of temperature-switching approach for simulation of enhanced low-dose-rate sensitivity was estimated and discussed.

It was demonstrated experimentally that in ELDRS-susceptible operational amplifiers elevated temperature irradiation increases degradation rate of input bias current, while in ELDRS-free devices degradation rates at room and elevated temperatures are approximately equal.

Radiation degradation rate of base current in SiGe HBTs was experimentally investigated using X-ray irradiation source with Cu anode at room and low temperatures. The dependences of base and collector current on the emitter-base voltage of the transistors were measured during radiation impact and presented for different total dose levels and irradiation conditions.

We investigated the radiation sensitivity of dose-metrical sensors based on n-channel MOSFETs taking into account the effects of temperature and electrical modes. There were measured the output voltages V being equal to the gate voltage VG of MOSFET-based dosimeter as function of the radiation doses at const values of the drain current ID and the drain—source voltage VD (conversion functions), as well as the (ID − VG) characteristics before, during and after irradiations at different temperatures. It was shown how the conversion functions and the radiation sensitivities are depending on the temperature and electrical modes. It is found that the conversion functions V(D) have two characteristic regions for low and high doses (with negative and with positive radiation sensitivities). To interpret experimental data there were proposed the models of conversion function and its components taking into account the separate contributions of charges in the dielectric and in SiO2–Si interface.

Radiation hardened ADC with automatic offset voltage compensation was developed. TID radiation effect in the ADC was investigated at different temperatures. The designed ADC devices demonstrate high radiation hardness. Up to total dose level 100 krad(Si) any significant radiation induced drift didn't observed in transfer characteristics of all irradiated devices. It is achieved by using techniques such as application of automatic offset voltage compensation circuit together with enclosed layout transistors (ELT), located in ADC control logic. Also, edge-less n-channel MOSFETs with additional guard rings were used to increase the radiation hardness of digital interface and control logic of ADC. In contrast with control logic ELT not used in interface logic. Thus significant degradation of digital interface power supply current was observed unlike control logic power supply. Developed device can be considered as a good technical decision for self-diagnostic systems of electronic devices proposed for application under ionizing radiation impact, especially for systems of spacecrafts and satellites.

Possible physical mechanism of reduced low dose rate sensitivity in bipolar devices is described. The reduced sensitivity can be connected with a specific position of effective Fermi level relatively acceptor and donor radiation-induced interface traps.

Radiation degradation rate of input offset voltage in bipolar operational amplifiers was estimated experimentally. High degradation rate was observed in devices with high input offset voltage initial values and temperature drifts. Obtained results were discussed.

The results of measurements of current-voltage characteristics of SiGe transistors for different temperatures are presented. The extraction results of parameters of test structures of the silicon-germanium SiGe bipolar transistors are presented.

The impact of radiation degradation on the temperature dependence of electrical parameters of bipolar operational amplifiers is presented. Results of the researches can improve our understanding of physical and circuit radiation effects in bipolar operational amplifiers.

The application of the ELDRS conversion model for numerical simulation of the radiation degradation of input bias current in widely used voltage comparator is presented. The recurrence relations for numerical simulations were obtained and used calculations of the estimation of the radiation response of LM111 input bias current in real operation temperature conditions of TechEdSat satellite.