Optimal Design Of GCT Termination Structure With Variation Lateral Doping

The Integrated Gate Commutate Thyristor (IGCT) as a new power device has widely used in power electronics field, the blocking voltage and its stability is a very important to evaluate its blocking capability and reliability. In order to improve the blocking voltage capacity and chip utilization as well as its stability, the termination structure of GCT should be designed optimally. In this paper, the termination structure of the Variation Lateral doping (VLD)junction is studied for 4.5k V GCT device. Firstly, the structure of the termination blocking mechanism and the key breakdown characteristics of the VLD junction termination structure are studied by Sentaurus-TCAD simulator, and extracted the appropriate termination structure parameters. Then analyzed the influence of different passivation layers on the breakdown characteristics of the device. Lastly, the key process of GCT VLD structure is studied .The main research contents are as follows:Firstly, the characteristics of VLD junction termination and traditional design idea is analyzed, and proposed a simpler termination mask design method of GCT VLD termination structure, and simulated by Sentaurus-TCAD simulator. The results show that the VLD junction termination structure is superior to the traditional bevel and field limiting ring structure in terms of withstand voltage efficiency, stability and termination size. And the termination structure parameters is optimized.Secondly, The influence of passive film on the breakdown characteristic of GCT device is studied. The results show that the polarity of fixed charge (such as, positive or negative) and the charge density Qss in the passivation film have a great influence on the termination breakdown characteristics, and when the fixed charge density is greater than 1×109 cm-2 do not apply to VLD junction terminal structure.Thirdly, the key process of the GCT VLD is studied. According to the VLD mask parameters of the optimized design, and gives the specific implementation process of the VLD doping profile is given by the process simulation, and the blocking characteristic of the GCT VLD structure is verified. The results show that the proposed method is feasibility in this paper.The research results of this paper can provide a reference for the design of the termination structure of high voltage and deep junction device.