Research Of FS-IGBT With Ultra-Low Power Loss

The conductance modulation effect makes the IGBT device have a very low conduction voltage drop and low conduction loss.However,it also makes the turn-off loss of the device significantly increase.And thus,the contradictory relationship between the on voltage drop(Von)and the turn-off loss(Eoff)has become the the most important problems in the design of low power IGBT device.In order to improve the trade-off relationship between the Von and Eoff of the IGBT device and realize the ultra-low power IGBT,two novel ultra-low power FS-IGBT device are proposed.1、A novel carrier-stored trench bipolar transistor with a split-gate and a deep-trench(SGDT CSTBT)is proposed.The novel device features a split-gate and a deep-trench at the emitter side.In the off-state,the deep-trench and split-gate structure can effectively assist the depletion of the carrier stored layer(CSL)so that the electric field peak near the CSL junction is decreased.This alleviates the degradation of the BV caused by high doping CSL,so that the carrier accumulation effect is enhanced and thus a lower conduction voltage drop is achieved.Meanwhile,the step-shape trench modulates the electric field in the bulk,and thus increases the BV.The simulation results show that the SGDT CSTBT can maintain the BV of 1521 V when the doping concentration of the CSL is up to 5 × 1017cm-3.At the same time,the new structure can decreased the Von by 48.1% at the same Eoff when compared with the conventional CSTBT.In addition,the split-gate makes the new structure have the same miller capacitance as the conventional CSTBT,although the deep-trench is induced into the SGDT CSTBT.Therefore,the switching characteristic of the SGDT CSTBT is not significantly affected.At last,a feasible process scheme for SGDT CSTBT is provided in the thesis.2、A shorted anode lateral IGBT with electron barrier layer(EB-SA LIGBT)is proposed.The novel device is characterized by P+ electron barrier layer and N-high resistance path at the collector region.By introducing the electron barreier layer and the high resistance path in the collector region,the equivalent resistance near the collector is effectively increased.So that the bipolar conduction mode is turned on at a small unipolar current.Thereby,the snapback phenomenon is suppressed and the stability of the device in the application is improved.Simulation shows that compared with the traditional SA LIGBT and SSA LIGBT,the new structure can completely suppress the snapback phenomenon under the collector region size of the "4μm × 8μm".Moreover,on the codition of snapback free,the Von of the new structure is reduced by 52.4% compared with that of the SSA LIGBT under the same turn-off loss.At last,a feasible process scheme for EB-SA LIGBT is provided in the thesis.