Research On Total Dose Anti-radiation Hardening Technology Based On 45nm FDSOI Device

As the feature size of integrated circuits continues to shrink and their applications in aerospace are increasing,the radiation effect of semiconductor devices has attracted more and more attention.The stability of the circuit of bulk silicon process devices under irradiation is getting worse,while the silicon-on-insulator(SOI)technology is more stable in use in the irradiation environment due to its unique structure and good anti-latch-up effect,anti-single event effect,and anti-instantaneous radiation effect,so it is getting more and more attention.This article mainly focuses on the research on the total dose irradiation effect in the 45 nm FDSOI process.Through the analysis of the failure damage mechanism of MOS devices under irradiation,the gate oxygen,buried oxygen and field oxygen of FDSOI MOS under the influence of sensitive parameters devices are discussed.Using the fixed charge model method,the effect of the gate oxide trap charge on the electrical characteristics of the 45 nm unreinforced bar-gate NMOS device under different irradiations is studied by simulation.Combining the existing theory and simulation results,it is found that when the gate oxide layer is when the thickness is less than 10 nm,the effect of trapped charges generated in the gate oxide on the device can be ignored.For buried oxygen,two type of radiation-resistant reinforced structures are proposed.By using the radiation model method,the silicon nitride sacrificial layer and the silicon nitride sacrificial layer as the sandwich layer of the isolation channel above the buried oxide layer are simulated and studied.The simulation results prove that the introduction of the sacrificial silicon nitride layer can greatly reduce the influence of the buried oxide layer trapped charges on the sensitive parameters of the device.In addition,several anti-irradiation reinforcement structures are proposed for device's field oxygen.Aiming at the field oxygen,the fixed charge model is used to simulate and study four antiirradiation reinforcement structures of the parasitic transistor formed by isolating the field oxygen and the channel,and analyze the influence of the trapped charge in the field oxygen on the degradation of the sensitive parameters of the device under different irradiation.Summarized the application of various reinforcement structures and process realization.These types of radiation-resistant reinforcement structures are:1.H-shaped grid.By forming epitaxial gate regions on both sides of the trench,the direct contact between the trench and the field oxygen is isolated,thereby achieving the purpose of anti-radiation reinforcement of the structure.2.Ring grid.By making the gate into a ring structure,the entire channel is surrounded by the source region and the drain region,and the field oxygen is isolated outside the drain region.At the same time,since the drain region serves as an intermediate layer between the field oxygen and the channel,the electric field effect of the field oxygen trap charges on the channel under irradiation is eliminated,and a strong anti-radiation reinforcement ability is realized.3.Z-shaped grid.An additional gate region is introduced to the side where the field oxygen of the FDSOI NMOS device is in contact with the channel to isolate the contact between the field oxygen and the active region,so that a parasitic leakage path cannot be formed,thereby achieving the purpose of anti-radiation reinforcement.4.P+ heavily doped(Semi P+ Guard Ring,SPGR)isolation structure.By introducing an extra heavily doped P+ layer into the source and drain regions of the FDSOI NMOS device,the trapped charge of field oxygen cannot cause the parasitic conductive channel to turn on under irradiation,thereby eliminating the total dose radiation damage of the device.In addition,the structure does not introduce additional gate area,and has a smaller layout area while achieving good anti-radiation characteristics.Finally,a new type of radiation-resistant multi-metal heterogeneous gate dielectric structure is proposed.By simulating physical models composed of different gate metals and gate dielectrics,using the fixed charge method,the degradation of sensitive parameters caused by field oxygen traps in the heterogeneous gate dielectric structure under irradiation is analyzed.The research results show that,compared with the conventional bar-gate structure,the heterogeneous gate dielectric structure has less degradation of sensitive parameters under irradiation,and has better anti-irradiation ability,which lays the foundation for the future design of ultra-thin gate oxide MOS with anti-irradiation.