Characteristics Of N,V Co-Doped Extrinsic SiC Light-Triggered Thyristor

Due to the use of light pulse signals to trigger conduction,light triggered thyristors have the advantages of natural photoelectric isolation and anti electromagnetic interference,and have great application value in industrial fields such as optical automatic control.In general,4H-SiC light triggered thyristors use ultraviolet light source to trigger conduction in the intrinsic absorption mode,while the ultraviolet light source has the disadvantages of high cost,large volume and light pollution,which has aroused people’s interest in the research of 4H-SiC non ultraviolet light triggered thyristors.Therefore,utilizing the non intrinsic light absorption characteristics of N and V co-doped SiC materials,conducting simulation research on N and V co-doped non intrinsic 4H-SiC light triggered thyristors,optimizing device structural parameters,and exploring light triggered characteristics,has important research significance.The main research content of this article is as follows:1.A simulation model for N and V co-doped SiC materials has been established.The dark state voltammetry and transient response characteristics of SiC photoconductive switches(Nv=1.0×10¹⁷cm^-3,NN=1.0×10¹⁶cm^-3)were simulated using a coplanar electrode structure,and the research results are consistent with the experimental data reported in the literature,verifying the rationality of the model.2.A N,V co-doped non intrinsic SiC light triggered thyristor structure was proposed,and the structural parameters were optimized and designed.On the basis of analyzing the working principle of non intrinsic SiC light triggered thyristors,the forward blocking characteristics and opening characteristics of non intrinsic SiC light triggered thyristors were optimized and designed.Simulation shows that the thickness of the long base zone is 200μm.N impurity concentration is 7.0×10¹⁴cm^-3,V impurity concentration of 5.0×10¹⁴cm^-3,the forward blocking voltage of the device is about 17.96kV.SiC light triggered thyristor exhibits direct conduction characteristics when triggered by a light pulse signal with λ=0.532μm@400mW/cm².3.The light triggering characteristics of N and V co-doped non intrinsic SiC light triggered thyristors were studied.When the concentration of N impurities in the long base region is 2.0×10¹⁴cm^-3,V impurity concentration at 2.0×10¹³cm^-3-1.0×1015cm^-3,there is little difference in the light triggering characteristics of the device.As the minority carrier lifetime in the long base region decreases,the delay time of the device gradually increases.As the optical power density increases,the turning on voltage of the device gradually decreases,and the turn-on response speed gradually becomes faster.By using the light pulse signal of λ=0.532μm,power density of 500mW/cm² and pulse width of 2.0μs trigger,the opening delay time t_d and current rise time t_r of 4H-SiC thyristor with gate slot are approximately 0.97μs and 503ns.The t_d and t_r of the gate slot free 4H-SiC thyristor are about 1.67μs and 538ns,increased by approximately 72.2%and 6.7%respectively,compared to before.