Research Of Typical Radiation Effects On Semiconductor Devices And 2D Semiconductor Materials And The Corresponding Simulation Technology

As we all know,the silicon-based and wide bandgap semiconductor devices(or chips)have been widely used in the new generation of information technology fields such as 5G,internet of things,big data analysis,cloud computing,artificial intelligence,etc.,as indispensable core components.The"Depth"layout towards 2030 released in China's National Science and Technology Innovation Plan will build a national advanced technology system focusing on"Deep Space,Deep Sea,Deep Earth and Deep Blue".Among them,Chang'e,Shenzhou,Beidou navigation satellites and other instruments(or space vehicles)operates in the vastness of space with a background of high or very high energy cosmic rays.The evaluation and detection of the radiation effects are critical to the proper functioning of the spacecraft or satellite.Besides,in the fields of national security equipment and nuclear power,radiation effect is also related to the stable operation of devices,circuits and systems.It can be concluded that study the radiation effects of various semiconductor materials,devices and integrated circuits as well as realize the accurate simulation,evaluation and detection under radiation conditions are of great significance and research value.In view of the above,under the support of the President Funding of Chinese Academy of Engineering Physics(No.2014-1-100)and the National Natural Science Foundation of China(No.61705203),the laser simulation of?-ray radiation and the compound radiation of?-ray and neutron for typical silicon and wide bandgap semiconductor devices were systematically carried out in depth.At the same time,considering the current research hotspot of semiconductors-two-dimensional semiconductor materials,its fast neutron radiation effects were studied for the first time.The feasibility of the corresponding simulation technology was also discussed.The main content of this thesis includes:(1)On the basis of extensive research and sufficient reviewing of related domestic and international literature,the background and research significance of this thesis was clarified,the research progress of radiation effect worldwide was summarized,and the development trend together with the main problems to be solved at present of laser simulation technology were analyzed.Furthermore,for the most widely used molybdenum disulfide material in two-dimensional semiconductor material scope,the research progress of its radiation effect was reviewed.The above clarify the basis research content of this thesis.(2)The basic theory of dose rate effects and laser simulation technology was described,based on which the“ionization-transport-photocurrent”physical model was constructed.Then the equivalent relationship between the laser intensity and the dose rate was quantitatively calculated,the factors that affect the laser simulation accuracy were analyzed.These work provided solid theoretical support for the design and experimental research of laser simulation.According to the insufficient accuracy of the existing method based on the excess carrier generation rate to obtain the equivalent coefficient,an improved method to calculate the equivalent coefficient based on the peak photocurrent was proposed in combination with the finite element numerical analysis.Theoretical and experiments were carried out to check the improved method.The results prove that the peak photocurrent calculation method is suitable in practical applications with better accuracy.Further,according to the limitations that still exist in the peak photocurrent calculation method,such as only one parameter is used in calculation,equivalent range is narrow under high dose rate,a brand-new calculation method of equivalent coefficient based on total charge was proposed.The accuracy,effective range and usable conditions of the two calculation methods based on peak photocurrent and total charge are compared theoretically and experimentally.The results show that the total charge calculation method not only has a wider equivalent range,but also keeps a better simulation accuracy compared with the other method.It is especially suitable in the case with high dose rate.(3)Two sets of experimental systems for laser simulation of dose rate effect were designed and constructed.For typical silicon-based and wide bandgap semiconductor devices,the does rate and laser simulation experiments were carried out.From the transient photocurrent responses of the devices under the two radiation,the feasibility of the constructed laser simulation system were proved.Then the influence of metal coverage of silicon-based devices on laser simulation performances was investigated.It was found that the metallization layout could change the linear relationship between the equivalent coefficient and the metal coverage,which means the limitations of only relying on the metal coverage as the correction factor to calculate the equivalent factor.(4)The radiation damage mechanism of silicon-based devices in an environment of both neutron and?-ray,and the changes of the photocurrent response of the devices after neutron pre-radiation were studied.The laser simulation technology was used to construct the compound radiation environment for the first time,and the feasibility of constructing the compound simulation environment of?-ray and neutron by pulse laser and neutron was verified.(5)The micro-scale behavior and physical mechanism of MoS₂ under fast neutron irradiation were characterized.The results showed that a large number of S and Mo atoms in MoS₂vacancies were produced in a very short time by fast neutron radiation.The moving S atoms were released by simple gases or volatile substances,while the moving Mo atoms remained on the sample surface by forming oxidation products.These would finally lead to the quenching and redshift of the photoluminescence spectra,as well as the broadening and redshift of Raman spectra.Based on the results of neutron radiation,the feasibility of using ion bombardment to simulate neutron radiation effect was discussed,believing Argon ions have great potential.The research fields of this thesis cover laser technology,nuclear physics,semiconductor physics,electronic science and materials science,including theoretical modeling,numerical simulation,system design and experiments.The characterization and analyses of micro-scale phenomena of new semiconductor material are also contained.The thesis enriches the knowledge of the laser simulation technology of semiconductor radiation effects,promote its development and practical applications,as well as enhance the understanding of the radiation effects of two-dimensional semiconductor materials.In addition to publishing papers in SCI journals or academic conferences,and authorizing invention patents,the research findings of this thesis also won the first prize of annual Science and Technology Award of Institute of Electronic Engineering of China Academy of Engineering Physics.