Numerical Simulation Of Ionizing Radiation Effects And Study On The X-ray Dose Enhancement Effects For Integrated Circuit

Recently years, it is becoming one of the important topics to study the effects and mechanisms of ionizing radiation for semiconductor devices and integrated circuits and to improve their radiation hardening in microelectronics field. Radiation hardening electronics has been become a comprehensive marginal subject and making full use of important action. The effects of ionizing radiation are simulated and dose enhancement effects for X-ray are studied in the paper. The main contributions in this thesis are as following:Using two-dimensional numerical method, SEU for MOSFET and SEB for N channel VDMOSFET are simulated. From the theory, a reliable approach is set up for analyzing device 's SEU. Collective charge of upset depending on LET for specific device structure is calculated for different particles LET. The results of simulation are consistent with the model of charging funnel. The effect of Single Event Burnout is investigated. The simulation results match experimental results well and are of great interest for a better understanding SEB of the occurrence of events. The effects of the minority carrier lifetime in the base, the base width and the emitter doping concentration on SEB susceptibility are verified. Some hardening solutions to SEB are provided. It is helpful to study the effects and mechanisms of Single event Phenomenon using heavy ion micro beam.Donor/Accept nature of total dose radiation-induced interface traps is analyzed. The post-irradiation behavior of the MOSFET has been simulated. It can be seen that the acceptor interface traps are negatively charged and the donor interface traps are neutral when the Fermi level is near conduction band (inversion for N-channel MOSFET), leading to a positive threshold voltage shift contribution from the interface traps. When the Fermi level is near the valence band (inversion for P-channel MOSFET), the accept interface traps are neutral, and the donor interface traps are positively charged, leading to a negative threshold voltage shift contribution from the interface traps. The model is found to be in good agreement with experimental results. An excellent evaluation approach is provided for accurately prediction of total dose radiation hardening to ionizing radiation.Transient radiation response for microcircuit PN junctions with enhancement photo current models is calculated. On the basis of Wirth-Rogers photocurrent models, the enhanced models include two additional effects such as high injection effects on excess minority carrier lifetime and electric fields in the substrate. These effects are mostpronounced in high resistively material. An excellent evaluation approach is provided for accurately prediction of transient response of modem microcircuit PN junctions to ionizing radiation. The behavior of PN junction device that is under EMP with different rapid-rise time has been simulated and analyzed. The effects such as two-dimensional current passage are given which could not be provided by one-dimensional device simulation. The whole process during which the device is under working, lapse and burnout are described in detail.A multiple parallel plate Aluminum ionization chamber has been designed for the study of dose distribution at and near the interface of different materials. Using the ionization chamber the measurements of dose gradient distribution at and near the interface of Kovar/Au1Al~ Pb/AL Ta/Al have been done for 30-lOOkeV x-rays with wide spectrum isotopic radiation accelerator and DEFs are provided. The experimental results are firstly published at home and abroad. DEF for interface of different materials is calculated by Monte-Carlo simulation of particle transportation, and the results are consistent with measured dose-enhancement factor. A reliable evaluation approach of theory is provided for studying x-ray~s dose enhancement.It has been proven that dose enhancement factors (DEF) near the different interface materials are different from dose damage enhancement factors (DDEF) near the same different int...