Design And Analysis Of SJ-IGBT Based On TCAD

Insulated gate bipolar transistor(IGBT),as a typical switching device in the field of power electronics,has the advantages of large input impedance,low forward voltage drop and low driving power.It also plays an important role in the switching power supply,household appliances,orbit transportation and other fields.However,there is a contradiction between the forward voltage drop and the turn-off loss in the conventional IGBT.Thus,it is always a difficulty to optimize the trade-off between forward voltage drop and turn-off loss effectively in IGBT design.In order to solve this problem,On the basis of IGBT theory,the Super Junction structure is introduced in the drift region of the device in order to further improve the comprehensive performance of IGBT.In this paper,the characteristics of SJ-IGBT device is simulated and analyzed by using Medici TCAD software.The research contents are as follows.Firstly,the working principle of SJ-IGBT device is analyzed,and the influence of pillar width,pillar thickness,pillar doping concentration on the static and dynamic characteristics of the device are studied When the P pillar and N pillar maintain charge balance,the breakdown characteristic of the device is obviously better than FS-IGBT's.When the P pillar and N pillar keep charge imbalance,the breakdown voltage is reduced correspondingly,and the decrease range is greatly related to the doping concentration of the pillar regions.Due to the affection of doping concentration of the pillar regions and the FS layer,there are unipolar and bipolar transport modes during the on-state of the IGBT.The results show that the turn-off loss of the SJ-IGBT device is reduced by 39.96%compared with the FS-IGBT device when the forward saturation voltage drop is 1.6V.Therefore,the Super Junction structure can improve the performance of the device effectively.Secondly,the characteristics of Semi SJ-IGBT device is analyzed.The results show that the breakdown voltage increases with the increase of the thickness of the pillar regions.Meanwhile,the forward voltage drop is easily affected by the doping concentration of the pillar regions.In order to reduce the forward voltage drop of Semi SJ-IGBT,the characteristics of Semi SJ-IGBT device with N barrier is studied.The results show that the N-barrier layer can reduce the forward voltage drop of the device effectively.Thirdly,based on the Semi SJ-IGBT structure,a novel Semi SJ-IGBT with electron extraction channel is proposed.During the turn-off process,an NPN transistor at the bottom of the device can provide an extraction channel for the electron carrier,which accelerates the turn-off speed of the device and reduces the turn-off loss.The results show that the turn-off loss the forward saturation voltage drop is 1.25V.Therefore,the device performance can be effectively improved.Fourthly,based on the Semi SJ-IGBT structure,a novel Semi SJ-IGBT with N pillar is proposed The hole injection efficiency of the collector is adjusted by intixxiucing N pillar in the P+ collector region,thus reducing the turn o:ff time of the device.The results show that the tum-offfloss of tihe new device is reduced by 37.03%compared with the Semi SJ-IGBT device when the forward saturation voltage drop is l125 V.Therefore,the device performance can also be effectively improved.