Research On Single Event Effect Mechanism And Model Of MOS Devices

Radiation effects are important factors in the space environment leading to functional failure and performance degradation of aerospace components,and single event effects are important parts of radiation effects.When a high-energy particle bombard a device that is in operation,it can induce functional errors or permanent damage to the device.In future aerospace applications,the demand for small-scale process CMOS devices and high-voltage power devices will become larger and larger.As the process size of CMOS devices continues to decrease and the operating voltage of power devices increases,the corresponding singleevent effect sensitivity problem becomes more and more serious.For small-scale process CMOS devices,single-event effects are mainly single-event transient effects(SET),singleevent upset effects(SEU),etc.,while for single-event effects of high-voltage power devices,there are mainly single-event burnout effects(SEB),single-event Gate Rupture effect(SEGR),single-event latch-up effect(SEL),etc.At present,there are still many problems to be solved in the single-event effect simulation technology of the device.In the single-event effect of CMOS devices,the organic integration of different levels of simulation technology cannot be realized.The establishment of single-event effect HSPICE model based on the device-level single-event effect analysis results is the key to support for circuit-level simulation of SEE.However,the current single-event effect HSPICE model cannot accurately describe the parasitic RC characteristics of the device during the particle acting on a device process and cannot cover the relationship between the device's electrical properties and particle parameters.In the research of VDMOS single-event effect,the traditional 2D TCAD simulation cannot achieve accurate quantitative analysis of the singleevent burnout characteristics of VDMOS devices.In this paper,the mechanism,sensitivity and related model technology of single-event transient effect of CMOS devices and singleevent burnout effect of VDMOS devices are studied mainly based on 3D TCAD simulation and combined with single event experiment results.In terms of single-event transient effect of CMOS device,based on particle simulation software GSEAT that the core of it is GEANT4 and Visual TCAD device simulation software,the 3D TCAD device structure of 65 nm CMOS device is constructed and the single-event effect mechanism of CMOS device and parasitic RC characteristics of the device during the action of incident particles are studied.Based on the results of TCAD simulation analysis,the single-event effect HSPICE equivalent sub-circuit model of CMOS devices is established,which provides support for circuit-level simulation of SEE.Further,the electrical characteristics of the device under the actions of different incident particles with different parameters(incident position,LET,incident angle,etc.)were analyzed by TCAD.The results show that the effective length and charge density of the "funnel" charge distortion region formed by different incident particles with different parameters are different,and the "funnel" parameter is an important factor affecting the single particle effect of CMOS devices.In terms of CMOS device output current characteristics,the difference in incident particle parameters ultimately manifests as a difference in current pulse peak characteristics and pulse width characteristics.Based on the results of TCAD simulation results,a model for describing the relationship between electrical parameters and particle parameters of the device is established,and an HSPICE equivalent sub-circuit model covering different incident particle parameters is formed,which provides support for describing the circuitlevel response caused by incident particles with different parameters.The hardened structure was simulated,and the guard ring structure is able to improve the performance of devices on single-event effects,but the improving capacity is limited.Finally,the HSPICE simulation results are compared with the results of single-event experiments provided by the National University of Defense Technology and Aerospace 772,and the accuracy of the model is verified.In terms of the single-particle burnout effect of VDMOS devices,the 3D TCAD structure of silicon-based 100 V VDMOS devices is built.Based on the heavy ion model,the singleparticle burnout effect of VDMOS devices is studied.Based on TCAD simulation,the process that single-particle current triggers the positive feedback and finally causes the single-particle burnout effect to occur is studied in depth,and a circuit schematic describing the single-event burnout effect of VDMOS devices is formed.The results of the analysis indicate that the mechanism that causes the VDMOS device to burnout is that the current pulse caused by the incident particles causes the source-substrate-drain parasitic BJT of the VDMOS device to turn on,forming a positive feedback,so that the current and temperature continue to rise and eventually the device is burned.Subsequently,the electrical characteristics of VDMOS devices under different incident particles with different parameters(LET,range,incident position,etc.)are studied.The relationship between the sensitivity of VDMOS burnout characteristics and particle parameters is discussed.The results show that the sensitive region of single-particle burnout effect is N-type light-doped epitaxial region of VDMOS devices.The ionization trajectory formed by incident particles in the N-type lightly doped epitaxial region is the active component to form single-particle current pulse.The maximum effective length of the ionization trajectory is limited by the thickness of the N-type lightly doped epitaxial region,and the amount of charge in the ionization trajectory determines the magnitude of the current pulse.Simultaneously,the resistance characteristics of the N-type lightly doped epitaxial region are also important factors affecting the single-particle burnout characteristics of the VDMOS device.When the length or incident position of the incident particles are different,the resistance of the N-type lightly doped epitaxial region is different,thus the voltage across base-emitter of the parasitic BJT is different,and which affects the difficulty of triggering the positive feedback process and causing the single-particle burnout effect.Compared with the traditional 2D TCAD simulation,the 3D TCAD simulation used in this paper can describe the device characteristics more accurately,thus realizing the accurate quantitative simulation of the single-event burnout characteristics of VDMOS devices.Finally,the simulation results are verified by laser equivalent single event experiment.The results of laser equivalent singleevent experiment show that when a VDMOS device is irradiated by a laser pulse with certain energy,the single-event burnout effect occurs,and this result is consistent with the simulation results.The possibility that instead of expensive high-energy particle experiments by cheap laser experiments is demonstrated,and an experimental method for conducting laser equivalent experiments is obtained.