Research On Radiation Effect Of Devices And SRAM Based On FDSOI Process

With the vigorous development of my country’s aerospace industry,the radiation damage of the space radiation environment to semiconductor devices is becoming more and more difficult to ignore.On the one hand,with the development of integrated circuit technology,the size of the device has also been reduced,resulting in an increasing sensitivity of semiconductor devices to radiation.On the other hand,as the size of devices shrinks,new processes and new materials have emerged,and the research on radiation effects of these new device structures is also more important.Fully depleted silicon-on-insulator(FDSOI)devices are currently one of the mainstream advanced semiconductor manufacturing processes.Compared with traditional processes,due to their special structural features,they have low power consumption,high integration,and strong single-event latch-up resistance.Etc.However,as the size of FDSOI devices gradually shrinks,the research on radiation effects of small-size FDSOI devices is still of great significance.This dissertation mainly carried out more accurate 3D TCAD modeling of 22 nm FDSOI devices to provide support for subsequent research.The single event transient effect(SET)of the FDSOI device was studied based on the modeled model,and the inverter and the four-tube SRAM cell were modeled and their single event characteristics were simulated based on the device.The specific research content and results are as follows:First,using Sentaurus TCAD software to perform a detailed device-level single-event transient simulation of the 22 nm FDSOI device.First,a three-dimensional modeling of a single device was carried out,and the device was calibrated to obtain a three-dimensional model that can faithfully reflect the process parameters and electrical characteristics of the actual device.The device-level simulation function of TCAD is used to study the influence of different single-event incident conditions on the transient current of the drain terminal of the FDSOI device.Mainly study the impact of heavy ion incidence depth,LET value,incidence position and incidence direction and other factors to find out the sensitive area of the device.The simulation found that with the increase of LET value and angle,the transient pulse width and height after single particle incident increased,and it was found that the sensitive area of the FDSOI device is the channel-drain P-N junction.Second,a single event simulation was performed for an inverter composed of 22 nm FDSOI devices.The inverter unit commonly used in digital circuits is modeled by TCAD,and the influence of its single event transient effect on the circuit is studied through the simulation function of TCAD.It is found that as the LET value increases,the time for the circuit output voltage level to switch is longer.Third,a single event effect simulation was performed on 22 nm FDSOI SRAM in TCAD.Firstly,the 4T SRAM cell is modeled by TCAD.Analyze the research on the storage node flip of SRAM memory cell under different incident conditions.The analysis shows that a transient current will be generated at the drain terminal after a single event is incident.For a22 nm FDSOI SRAM cell,if the peak value of the transient current exceeds the inversion threshold of the SRAM cell,it will cause a single event inversion(SEU)in the cell..Moreover,when a single particle is incident between the channel and the drain of the 22 nm FDSOI NMOS in the off state,the SRAM cell is more prone to single-event inversion than a single particle incident on other positions.This paper studies the single event transient characteristics of 22 nm FDSOI devices,and further explores the single event effects of inverters and SRAMs built by 22 nm FDSOI through the study of devices.The obtained simulation results have guiding significance for circuit design and subsequent circuit testing.