Interrelation of equivalent values for linear energy transfer of heavy charged particles and the energy of focused laser radiation

The estimations of equivalent values for linear energy transfer of heavy charged particles based on the results of experimental investigations of sensitivity of LSICs to local radiation effects with the use of the procedure of local laser irradiation are presented. The possibility of recalculation of the energy of laser radiation into equivalent values of linear energy transfer with the use of the measurements of the ionization reaction in the supply circuit of LSIC is substantiated. Uncertainties caused by the characteristics of the interaction of optical radiation with semiconductor structures are eliminated in the suggested procedure.     

Experimental studies of the adequacy of laser simulations of dose rate effects in integrated circuits and semiconductor devices

Comparative experimental studies of the responses of typical representatives of integrated circuits (ICs) and semiconductor devices (SDs) with various designs to high-energy pulsed ionizing radiations from simulation facilities and laser simulators have been carried out. The differences between the hardness values under exposure to radiations from simulation facilities and laser simulators have been found to be no larger than the dosimetry errors when the power supply ionization current calibration procedure is used. The shapes of power supply ionization currents and output voltages in the ICs are almost identical qualitatively. The levels and patterns of the functional IC failures are completely identical for both types of radiation sources. As a result, we have proven that a joint application of simulation facilities and laser simulators provides a rational combination of the reliability and efficiency of testing ICs and SDs for hardness to dose rate.     

Ab Initio Calculations and Measurements of Thermoelectric Properties of V2O5 Films

Density functional theory and the Boltzmann transport equation were used to calculate the thermoelectric transport coefficients for bulk V₂O₅ and MV₂O₅ (M = Cr, Ti, Na, Li). The structural relaxation for the given compounds based on the ABINIT code was observed. The temperature dependences of the Seebeck coefficients as well as electrical and thermal electrical conductivities of all relaxed structures displayed anisotropic behavior. Electrooptical measurements of thermoelectric properties were carried out on V₂O₅ thin films obtained by thermal evaporation with different post-annealing treatments. A Seebeck coefficient of ?148 μV/K at T = 300 K was obtained in the in-plane direction for V₂O₅ thin films with thickness less than 100 nm.     

IC’s radiation effects modeling and estimation

The approach for IC's radiation hardness estimation and fault prediction is presented in this paper. It is based on the implementation of low-energy laboratory simulation sources (laser, X-ray, etc.). The possibility of radiation simulator application is based on similarity of physical processes in semiconductor structures causing IC upsets and failures under the radiation environment and under simulation sources. The analysis of adequacy is performed for total dose effects, single event effects, displacement effects and transient radiation effects. The application of imitators permits to change the expensive and low-productive radiation test installations with much more effective simulation sources, based on the dominant effects equivalence. The designed simulation test methods are proved to be an effective tool to different IC radiation hardness estimation and fault prediction in radiation environment.     

Dynamics of a Shock Wave in Laser-Induced Surface Air Breakdown

The amplitude and the time of arrival of a shock wave have been measured experimentally and calculated numerically at different distances from the region of the surface air breakdown by the radiation of a single-pulse YAG:Nd³⁺ laser for energy densities of 2.5–570 J/cm². Good agreement between the experimental and calculated values of the shock-wave amplitude beyond the breakdown region has been established. A more rapid propagation of the actual shock wave as compared to the calculated shock wave has been revealed for low energies of laser pulses, whereas a retarded propagation of the actual shock wave as compared to the calculated one has been revealed for high energies.     

Features of the Time Shape of the Pressure Pulses of Optical Air Breakdown

The time shape and amplitude of pressure pulses initiated by surface laser air breakdown for different energies of laser pulses (1–180 mJ) has been compared to the results of numerical gasdynamic calculations of unsteady explosive motions with allowance for counterpressure at distances of 0.2 to 30 cm from the breakdown region. It has been established that the experimental pressure pulse has the character of slowly damped quasiperiodic vibrations, whereas the calculated pulse is a bipolar single pulse of a much shorter duration. Good agreement between the experimental and calculated amplitudes of a positive pressure phase has been found throughout the investigated range, whereas the agreement between the corresponding amplitudes and durations of a negative pressure phase is limited in character. The differences observed in the experimental and calculated data have been attributed to the transformation of the shockwave motion to acoustic radiation.