Analysis And Design Of SiC-IGBT New Structure With Injection Enhancement

Silicon carbide insulated gate bipolar transistors(SiC IGBTs)not only have the advantages of high critical breakdown electric field,large breakdown voltage,and high operating frequency of SiC materials,but also have the advantages of easy driving,simple control,low on-state voltage drop and low loss of IGBT devices,which makes it the best choice for high-voltage(?10kV)and high-current applications such as high-voltage inverters and flexible AC/DC transmission systems.For SiC IGBT,reducing on-state voltage drop and improving the trade-off relationship between on-state voltage drop and turn-off loss has been a research direction in this field.Therefore,based on this research direction,this paper has carried out research work on a new type of planar injection-enhanced SiC IGBT.The main contents are as follows:1.A planar injection-enhanced SiC IGBT structure with Schottky contact(SC-IGBT)is proposed.By setting the contact between the emitter metal and the P-type base region as a Schottky contact,the hole barrier formed improves the carrier concentration on the emitter side of the SC-IGBT,thereby enhancing the conductance modulation effect,reducing the on-state voltage drop and optimizing the trade-off relationship between on-state voltage drop and turn-off loss.The results show that at100A/cm~2,the on-state voltage drop of SC-IGBT is 5.78V,which is 12.4%lower than6.60V of Con-IGBT;SC-IGBT has a turn-off loss of 2.33mJ at on-state voltage drop of6.44V,which is 47.5%lower than 4.44mJ of the Con-IGBT.Furthermore,based on the SC-IGBT,a planar dual injection-enhanced SiC IGBT structure with Schottky contact and Carrier storage layer(SC-CSL-IGBT)is proposed.The newly introduced carrier storage layer in SC-CSL-IGBT further reduces the on-state voltage drop and optimizes the trade-off relationship between on-state voltage drop and turn-off loss.The results show that at 100A/cm~2,the on-state voltage drop of SC-CSL-IGBT is 4.70V,which is18.7%lower than that of SC-IGBT and 28.8%lower than that of Con-IGBT;At the same on-state voltage drop of 6.44V,the turn-off loss of SC-CSL-IGBT is 1.32mJ,which is 43.3%lower than SC-IGBT and 70.3%lower than Con-IGBT.2.A planar injection-enhanced SiC IGBT structure with Schottky contact and P-type shield layer(SC-PSL-IGBT)is proposed.By introducing a P-type shield layer into the N-type carrier storage layer of the SC-PSL-IGBT,avoiding the adverse effect of the high-concentration carrier storage layer on the breakdown voltage,and it is possible to further increase the doping concentration of the carrier storage layer,reducing the on-state voltage drop and optimizing the trade-off relationship between the on-state voltage drop and the turn-off loss.The results show that at 100A/cm~2,the on-state voltage drop of SC-PSL-IGBT is 4.34V,which is 34.3%lower than that of Con-IGBT and the turn-off loss of the SC-PSL-IGBT is 1.15mJ at on-state voltage drop of 6.44V,which is 74.1%lower than that of the Con-IGBT.