Research Of 6kV/3kA RC-GCT

With the continuous growth of the global economy,power electronics technology is constantly developing towards high power,high voltage and large current.In compliance with the needs of the times,people developed the Gate Commutated Thyristors(GCT)in high-power power electronic device.In this paper,the differences in structure and working principle of GCT and GTO are analyzed,and the characteristics of GCT in buffer layer,transparent anode and reverse guide technology are described.Based on years accumulation of the technology of high-power device production of Xi'an PERI Ltd company,we establish the structure parameters and process flow of the 6kV/3kA RC-GCT,and the forming technology of the cathode comb bar is determined.The experimental verification of the process production is also carried out.First,the working principle of GCT is studied,and the design of structural parameters is discussed from three aspects: buffer layer,transparent anode and reverse guide technology.In order to achieve high voltage,and reduce the pass loss and switching loss,a buffer layer is introduced between the base area of the thyristor and the emitter,which reduces the thickness of the silicon wafer.The transparent anodes makes electrons pass through the anode very easily,it looks like that the anode image is transparent,and the required trigger current is very low.When GCT is turned off,the carrier can pass through the anode directly,shortening the closing time and reducing the switch off loss.Using reverse conductance technology,the thyristor and diode can be used on the same device,and the volume of the circuit can be reduced.Then,the structure characteristics of GCT are studied.The structure parameters of 6kV/3kA RC-GCT are established in this paper.The simulation results of the simulation software verify the feasibility of the device structure.Finally,the manufacturing scheme and process of 6kV/3kA RC-GCT are studied.In order to reduce the loss in production,the anode should use transparent anode,and the difficulty of thin size and low doping concentration should be solved in transparent anode.The process is difficult for the selective deep diffusion of the P base area,and it is necessary to adopt the groove isolation.The buffer layer is very thick and the concentration is low.So in the process of diffusion,it is important to control the diffusion time very strictly to ensure the uniformity of diffusion.In order to make the device switch more uniform,the structure uses an integrated diode placed in the center of the chip.Analyze the structural advantages of integrated diodes in the center of the chip.This structure enlarges the central gate size and makes the switching characteristics more uniform.At last,the test results of the final product verify the feasibility of the GCT structure design.