Study On Modeling Method Of Total Dose Radiation Effect Of MOS Structure

MOS structure of electronic devices as the key part of integrated circuit elements,Ionizing radiation can cause significant charge accumulation in the oxide layer of its insulator.Studies show that trap charge in the oxide layer formed by trapping hole in the oxide layer and in-terface trap charge formed at the Si-Si O₂ interface are the two main types of charge induced by radiation.These two trap charges can cause changes in the electrical characteristics of the device,leading to device performance degradation or failure.And with the increase of"moon and fire exploration"missions,research on the influence of irradiation temperature on ion-izing radiation of MOS devices has also attracted attention.With the decreasing of the size of the device,more accurate radiation effect model is needed.The aim of this paper is to study the mechanism of total dose radiation damage of MOS structural devices and to establish a set of numerical models of radiation damage that can be used to analyze devices at different doses and temperatures more accurately than those previously studied.In the process of establishing the numerical model,the relationship between radiation dose and radiation temperature and the generation of two kinds of trap charges is considered.Finally,the total dose radiation model proposed in this paper is well fitted with the experimental data of relevant literature and the experimental data in this pa-per.The research of this paper can be summarized into the following four parts:（1）Based on the physical mechanism of total dose radiation effect of MOS devices,the gen-eration mechanism of oxidation layer trap charge and interface state trap charge is described,and the influence of irradiation temperature on each physical process of total dose radiation and the generation and annealing of two kinds of trap charge is analyzed.（2）An improved model of total dose radiation oxide layer was established.It is found that the fitting error of the general model of the total dose radiation oxide layer is large with the data of several experimental literatures.This is because the heat-induced annealing effect of the oxide layer trap charge is more and more obvious with the increase of the irradiation temperature,and the effect of tunneling annealing on the generation of the oxide layer trap charge is also closely related to the irradiation dose.Finally,the general model of oxide layer is improved and the effects of tunneling annealing and thermal excitation annealing are considered.The verification results show that the fitting accuracy of the new improved oxide layer model is significantly improved.（3）The Weibull probability distribution model of interface state trap charge under the influ-ence of irradiation temperature is established.The study found that under the influence of different irradiation temperatures,the change curve of the interface state trap charge is similar to the Weibull distribution in the probability distribution model.Combining this finding with the most recognized"two-stage"model of hydrogen protons at present,the Weibull proba-bility distribution model of the trapped charge in the interface state under the influence of different irradiation temperature is established.Then,based on the K-S（Kolmogorov Smirnov）statistics test method,the confidence band of K-S test is constructed in MATLAB,and the accuracy of the interface state trapped charge obeying Weibull distribution under the influence of different irradiation temperature is observed intuitively.（4）The total dose radiation experiment was designed to verify the total dose radiation model in this paper.According to the oxide layer improvement and the interfaces state Weibull prob-ability distribution model,the threshold voltage drift total dose radiation model is ob-tained,which was fitted with the experimental data of several references,and the fitting re-sults were good.Final design the total dose of radiation experiments,the experiment con-ducted in the Chinese Academy of Sciences institute of physics and chemistry technology in xinjiang,the experimental device under different dose point transfer characteristic curve is obtained.Through linear extrapolation method to extract the threshold voltage,which is fit-ted with the total dose radiation model proposed in this paper,further verifying the accuracy of the total dose radiation model proposed in this paper.What has been discussed above,this thesis deeply studies the total dose radiation effects of MOS devices,we will further improve the numerical model,the total dose radiation effects on the use of computer software simulator in irradiation environment behavior,can improve the precision of computer simulation for integrated circuit radiation-hardened reinforcement technology research to provide certain reference.