Design And Simulation Analysis Of 1700V RC-IGBT

IGBT is currently one of the most mainstream power devices.In order to reduce the cost of manufacturing and packaging,it has been proposed to integrate the IGBT with its freewheeling diode as a reverse-conducting IGBT(RC-IGBT).The most important feature of the RC-IGBT is that it has both forward and reverse turn-on capabilities,and at the same time the biggest problem is that Snapback occurs when it is turned on.How to suppress or even eliminate Snapback phenomenon is one of the hot spots of RC-IGBT research.In this paper,the Snapback phenomenon of RC-IGBT is studied,and the method of solving this phenomenon preliminary is found.On this basis,a new RC-IGBT structure is proposed,and its advantages and disadvantages are simulated and analyzed.This article mainly consists of the following parts:1.Briefly introduces the development history of IGBT and RC-IGBT,the advantages and disadvantages of RC-IGBT and the problems to be solved in design,and the basic characteristics of integrated P-i-N power diodes in RC-IGBT.2.Analyzes the three working states of the traditional RC-IGBT and the principle of the Snapback phenomenon in the forward conduction process.The simulation results show that the method of reducing the length of the cell N-an anode is the simplest and effective way to suppress the Snapback phenomenon,but at the same time,the reverse conduction characteristic of the device is deteriorated.And then explained reasons of the RC-IGBT breakdown voltage is higher than the same parameters under the conventional IGBT.3.A new type of RC-IGBT structure is proposed.The main idea is to use the area of the junction terminal part where the reverse conduction does not flow current by replacing the P-anode of the anode with N-anode,so that the junction terminal part also has the ability to reverse conduction.The new RC-IGBT achieves optimization to the traditional RC-IGBT in its forward and reverse turn-on properties,and does not require additional process steps.4.Points out the disadvantage of the new RC-IGBT that its current will be too concentrated at the edge cell cathode near the junction terminal,which will lead to the opening of the parasitic thyristor,so that the device fails in the process of reverse recovery which switches from the reverse continuity state to the forward blocking state.Reducing the the N-anode length of the junction terminal part can cause the device's reverse recovery fails at greater current and the negative impact is small,is an excellent way to solve the problem of reverse recovery failure.