Research On Single Event Failure Mechanism Of SiC Schottky Diode

Wide band-gap semiconductors have superior material properties.Compared with siliconbased power devices,wide band-gap semiconductors can work at higher temperatures,voltages,and switching speeds.Therefore,under the condition that the performance of traditional silicon-based power devices had been limited,a new generation of power devices gets gradually developed.These new power semiconductor devices have higher power density and operating frequency,which will greatly improve the performance of existing power electronic devices.As a representative of wide band-gap semiconductors,silicon carbide(SiC)has become the most concerned semiconductor material for new power devices due to its excellent performance and gradually matured process.SiC has excellent thermal conductivity,resulting in a smaller heat dissipation volume compared to silicon materials,which provides a wide range of application prospects in the aerospace field,thus the antiradiation performance of SiC power devices needs to be studied urgently.The main research content of this thesis is divided into three parts:(1)First the layout design of the SiC junction barrier Schottky diode is completed by Tanner EDA L-edit.The manufacturing and dicing afterwards is carried out with the Zhuzhou China CRRC Times Electric Co.,Ltd.SiC device production line,a test of forward and breakdown characteristics of SiC junction barrier Schottky diodes as well.The test data shows that the forward conducting current of the device can reach 20 A at 25 degree,showing a positive temperature coefficient;the reverse breakdown voltage reaches 1792.0V,and the reverse saturation current about 1.44 n A,which implicit good switching characteristics.(2)After a SiC material model established based on Geant4,we did a simulation on the single incident LET distribution results of different light particles and heavy ions that vary in atomic weights,in different incident energy ranges,the incident times at each energy stage increasing to 1000 meanwhile.The material's absorption of particle dose degree is estimated by whether the elastic scattering,nuclear reaction or secondary particles come into being,which is analyzed through the LET distribution curve that drawn with the average value of the results of different energy segments according to the principle of Monte Carlo statistics.The result shows that the LET value of protons oscillates obviously at low-energy incidence,and then decreases exponentially when the energy gets lower than 10-1Me V.There's a LET peak of Alpha particles near 1Me V,while Beta particles decrease exponentially during the energy dropping,when the energy deposited by Gamma particles is so little that it goes almost directly through the material.There are peaks of the 10 heavy ions used in the simulation occured in the low-level and high-level regions,which appears in the shape of double peaks,and as the atomic number increases,the two peaks become more obvious and gradually get closer to each other,the peak value increasing as well.With altering the particle bombardment angle and the target doping concentration,then observing the path of the particles under different conditions,the LET distribution curve is drawn and the analysis is done.(3)With the SiC Schottky diode device structure model established based on Sentaurus TCAD,the paper holds a simulation verification of the static parameters and breakdown characteristics of the device model as the physical process model and electrical characteristics extraction method set,after which a trial on transient single particle incidence on the device is performed and the statistical transient current curve is drawn.By changing the initial LET value,incident angle and depth of the incident,the transient current curve and the total charge value generated under different experimental conditions are extracted,which serve as the basis for analyzing the influence of the energy deposited by heavy ions in the device on the electrical characteristics of the device.