Design Of Split Floating P-Region Insulated Gate Bipolar Transistor

IGBT is the core component of power electronic system,which is widely used in the fields of smart grid,rail transit,wind power generation and new electric vehicle.As the global energy transformation and the popularization of the concept of energy conservation and environmental protection,IGBT is bound to have a broader space for development.So far,IGBT research hotspots have focused on the trade-off relationship between on-voltage and turn-off loss,blocking capability and short-circuit capability.Based on the above reasons,the IGBT with split FP structure are proposed to improve IGBT performance in this paper.The main contents of this article are as follows:1.A IGBT with a split FP structure is further proposed.This structure divides a single floating P-region into three.Based on the characteristics of the potential change of the floating P region during the switching process,a PNP transistor hole path that can be automatically opened and closed is introduced into the floating P region.When the IGBT is turned on,the hole path is turned off to ensure the conductance modulation effect of the IGBT.When the IGBT is turned off,the hole path is opened to reduce the turn-off loss,and the V_CEsat-E_off trade-off relationship of the IGBT is optimized.At the same time,the proposed structure can effectively reduce the Miller capacitance,and can also effectively reduce the turn-on time.When its turn off,the potential of the floating P-region can be reduced,the electric field at the bottom of the trench can be shielded,and the blocking ability can be enhanced.The key structure parameters of the proposed structure are designed and simulated,and detailed analysis is performed in this paper.2.Process design of split FP structure IGBT.For the proposed structure,a process was established.At the same time,the TCAD simulation tool was used to simulate and analyze the thickness and resistivity of the N-drift region,the implantation dose and push-in time of the P-body,the trench gate depth,the thickness and resistivity of the FS layer,and the P+collector implantation dose.Then the influence of these factors on the breakdown voltage,threshold voltage and on-voltage drop are analyzed,and the cell structure that meets the design index is obtained.Finally,the terminal and layout are designed.Through design and simulation,the proposed structure has an 11%improvement in blocking capability compared to the floating P-region IGBT;When the gate resistance is5Ω,the Miller platform time is reduced by 48.8%and the turn-on time is reduced by16%;When the gate resistance is 30Ω,the turn-off time is reduced by 42.5%;At the same time,the V_CEsat-E_off trade-off relationship is optimized.Under the same V_CEsat,E_offff is reduced by 17.9%.It can be seen that split FP structure IGBT can effectively reduce the Miller capacitance,improve the blocking ability,and improve the V_CEsat-E_offff trade-off relationship.