Theoretical Investigation Of Backgate-related Single Event Effect In FDSOI Devices

With the development of space technology and the continuous improvement of chip integration,single event effect has become an important problem to threaten the reliability of electronic equipment,and the fully depleted silicon on insulator(FDSOI)has attracted wide attention in space applications due to its excellent radiation resistance.The structure of the back gate,which is the regulating threshold,is more and more critical to the transient current of the single event effect,and it is necessary to study and evaluate it in depth.In this paper,the contribution of collision ionization to the single event effect caused by heavy ion incident in the back gate region(well)is discussed at three levels:Firstly,the relationship between the transient current of single event with no back gate radiation effect and the potential barrier of PN junction in the silicon film region is established,then the law of the influence of the transient current of single particle is obtained through the results of the depletion layer thickness and the change of potential caused by ionization in the well,and finally,the closed state disturbance caused by the ionization current to the adjacent transistor is explored.Previous studies focus on results of single event effect,and this article to discuss in detail the simulation quantity changes of different time,It is found that the parasitic bipolar effect collection is mainly modulated by the source body barrier,and the correlation between the early disturbance of the single event transient current and the radiation ionization in the back gate region is clear by comparing channel incident and full incident.(1)Study on the single event effect mechanism of UTBB FDSOI devices based on back gate effect.Established UTBB FDSOI TCAD NMOS device model,adopt the method of channel incident consider no back gate under the influence of single event radiation effect,the analysis of the conditions of different order particle transient current and the reason of the difference and its differentiation in combination with the worst incident position and conventional bias voltage to the default simulation conditions: LET(0.2p C/mm),the incident position(0.029 mm),the back gate bias(0 V),the depth of the incident(7 nm).From different incident position to end the transient leakage current is found: the influence of the source node and the source of the starting point of interaction is to build the whole mechanism model,then use to analyze the interaction in two ways,Firstly,the difference between the complete transient current collection process and the drift current collection process in the MOS transistor is obtained by removing the source-body junction,Secondly,change the drain,source and the back gate bias,based on the variation trend of carrier distribution,potential distribution and current composition,the relationship between drift collection and parasitic bipolar amplification collection in the transient collection current of single event and the action rule of the potential barrier at both terminals are established in the comparison.(2)Study on the single event back gate effect of UTBB FDSOI devices.The simulation of full incident and channel incident was established to study the influence of back gate effect on the size,composition and charge collection mechanism of single event effect transient current.The relationship between charge collection efficiency and incident position is analyzed,and the sensitive region and mechanism of single event effect in UTBB FDSOI MOS device are further obtained.The effects of sourcing-drain voltage,back-gate control,BP layer doping and BOX thickness on the charge collection process of UTBB FDSOI devices are discussed.The relationship between back gate radiation and the original potential distribution in the well region is obtained.(3)Study on circuit charge sharing mechanism of UTBB FDSOI devices.The circuit charge sharing mechanism of UTBB FDSOI device was analyzed by TCAD full-scale simulation and mixed mode simulation.The influences of transistor spacing,backgate bias voltage,particle incidence angle and trap technology on charge sharing mechanism are discussed.The charge sharing mechanism of the UTBB FDSOI device in the same well is analyzed according to the radiation effect of the substrate.The effects of transistor interval,backgate bias voltage,particle incidence angle and well technology on the charge-sharing mechanism are obtained and explained.