The Investigation And Fabrication Of A LIGBT Device With Carrier Acceleration

Insulated gate bipolar transistor(IGBT)has rapidly developed into a typical representative of power semiconductor devices due to its advantages of high gate input impedance and low on-resistance.It is widely used in household appliances,industrial control,automotive electronics,new energy and other fields.Because of the large injection effect of the anode in the conduction stage of IGBT device,a large number of holes are injected into the drift region,and a conductivity modulation effect occurs in the drift region.Electrons and holes simultaneously participate in the conduction,and the on-resistance of the device decreases rapidly.After the gate of the device is off,the device's electronic conductive path is closed,and a large number of unbalanced electrons in the drift region do not have a fast release path,which can only be eliminated by recombination,then a long tail current phenomenon is formed.This limits the switching frequency of the device and increases the turn-off loss of the device.With the increasing demand for high-speed large-current switching devices in the power semiconductor market,researchers are working hard to find a solution to the contradictory relationship between the on-resistance and off-time of IGBT devices.Under this background,this paper proposes a new type of carrier-accelerated LIGBT device(CA-LIGBT).The CA-LIGBT device proposed in this paper is based on the traditional LIGBT device,and introduces a polysilicon auxiliary gate which is located above the drift region.During the turn-off phase of the device,During the turn-off phase of the device,the auxiliary gate can introduce a new electric field peak in the middle of the drift region,making the electric field distribution of the device in the entire drift region more uniform to improve the breakdown voltage of the device.During the turn-on phase of the device,the auxiliary gate can provide an additional electric field from the anode to the auxiliary gate,which acceleratesthe hole carriers injected into the drift region of the anode,thus improving the injection efficiency of the anode and reducing the on-resistance of the device.Moreover,during the turn-off process of the device,the auxiliary gate will also promote the injection of hole carriers into the drift region,so as to accelerate the unbalanced electron recombination speed in the drift region,thus shortening the tail current time of the device and reducing the device's turn-off loss.Based on the theoretical analysis of the CA-LIGBT device,a 400V CA-LIGBT device structure is designed in this paper.The device is modeled by TCAD software Sentaurus and various performance simulations are verified.According to the simulation results,compared with the traditional LIGBT devices,the CA-LIGBT device designed in this paper can greatly reduce the turn-off tail current time of the device while increasing the breakdown voltage and on-current density.In this paper,the process flow of 400V CA-LIGBT device is designed by using the process steps compatible with the traditional BCD process.After the simulation and verification of the process steps,the layout design is performed,and it is fabricated with the 6 inch 1.0?m process of Analog Foundries Co.Ltd.After the tape is finished,the packaging of the device is carried out,and the driving scheme of the device is designed,and the driving scheme is verified through the test work.After the 400V CA-LIGBT device test after fabrication,the breakdown voltage of the device was 350V,the on-current density reached 155A/cm~2,the off time of the device was 190ns,and the rise time of the anode voltage of the device was 90ns.