Research On Single Event And Total Dose Effects And Coupling Effects Based On UTBB-FDSOI Devices

This article aims to study the total dose effect and single event effect of the UTBB-FDSOI(ultra-thin buried oxide layer and ultra-thin body fully depleted SOI)device under the 22 nm process node based on the new generation TCAD simulation tools Sentaurus and Cadence's Specture.The research is divided into two parts: total dose part and single event part.In the total dose part,firstly,the smallest size device of UTBB-FDSOI under the 22 nm process node is modeled in three-dimensional device,that is,NFET and PFET with a widthto-length ratio of 0.08um/0.02 um.Then use the new Sentaurus-based simulation method of total dose to simulate the TID of NFET and PFET.The simulation results show:(1)Regardless of whether it is NFET or PFET,the worst bias state for the BOX layer is the transmission state(TG),and the worst bias state for the STI layer is the ON state(ON).From the perspective of the total dose effect on the overall electrical characteristics of the device,the worst bias state is the transmission state.That is to say from the side that the BOX layer has a greater impact on the device than the STI layer after the device is irradiated.(2)The larger the inclination angle of STI(the closer to 90°),the better its anti-total dose effect.(3)The higher the doping of the body region,the better the anti-total dose effect.(4)When the doserate is constant,the higher the radiation dose,the device's channel mobility will decrease due to the collision and scattering of a large number of carriers generated by the radiation,and the current density in the device's channel will increase.(5)When the total dose is constant,the device exhibits a significant doserate effect.In the long-term irradiation environment,the interface state caused by the low dose rate has a greater impact on the electrical characteristics of the device.(6)As the total dose increases,the transfer characteristics of the linear region and the saturation region of the NFET and PFET have negative drift.The threshold voltage,maximum transconductance,subthreshold swing(SS),Drain induced barrier lowering(DIBL),and switching current ratio of the device are all affected to varying degrees.(7)Under the irradiation environment,let NFET and PFET work in RBB mode and FBB mode to have certain anti-TID effect.In the single-particle part,firstly,the UTBB-FDSOI LVT NFET with a width-to-length ratio of 0.08um/0.02 um under the 22 nm process node is modeled for a three-dimensional device.Then use Sentaurus to study the single event effect of LVT NFET,and then add the single event pulse simulated by Sentaurus to the inverter and 6T SRAM in the form of a current source to study the impacts of the single event pulse on the output of the inverter,including SRAM single event upset phenomenon.Finally,the inverter and 6T SRAM have been reinforced at the circuit level.The simulation results show:(1)The worst bias state for single event incidence is OFF.(2)For short-channel devices,the single event sensitive position is near the center of the channel,while for long-channel devices,the sensitive position is at the junction of Body and LDD.(3)As the gate's length increases,the parasitic bipolar effect caused by SEE decreases.(4)With the increase of LET,the single event pulse and pulse width increase,and compared with the same size NFET device,the LVT NFET single event pulse is slightly smaller.(5)As the increase in drain's current and in temperature,which will cause the SEE to increase.(6)After the reinforced inverter and 6T SRAM on SEE,the inverter output is stable,and the single event upset(SEU)phenomenon no longer occurs in the 6T SRAM.Finally,a new simulation method for studying the coupling of total dose and single event effect is proposed,and the coupling simulation is carried out.The simulation results show that in the OFF state,with the increase of the total dose,the peak value of the single-event pulse current increases,but the pulse width decreases,and the collected charge on the drain increases.