Study And Optimization Design Of Dynamic Characteristics For 600V Super Junction Devices

As a representative of new power MOSFET devices,super junction power MOSFET devices achieve ultra-low specific on-resistance through unique charge compensation technology,which significantly improves device efficiency,and greatly reduces system power loss.They are widely applied in fields such as electronic products,lighting,power supplies,and automotive electronics.With the increasing operation frequency of super junction MOSFET devices,the requirements for dynamic performance such as switching speed and reverse recovery characteristics of devices in contemporary power systems are also constantly increasing,which puts forward new requirements for the optimization design of dynamic characteristics of devices.Therefore,this article focuses on the dynamic characteristics of super junction power MOSFET devices,including capacitance characteristics,switching characteristics,and reverse recovery characteristics.These electrical characteristics are optimized and verified through tape-out experiments.The main content and work on 600V super junction power MOSFET devices in this article are as follows:1.A 600V super junction power VDMOS device with small cell pitch is designed,and the basic parameters of the cell structure and terminal structure are determined through device simulation.Based on the multi-epitaxial/multi-implant process,the manufacturing of cell structure and terminal structure are simulated and the electrical characteristics of the device are obtained through simulation.The breakdown voltage and specific on-resistance of the device meet the requirements of the project.2.Based on the simulated device structure parameters and the process platform provided by the cooperative company,a detailed flow for the multi-epitaxial/multi-implant process is determined,and the layout design is carried out,mainly including cell,termination,corner,gate structure,and ESD.The super junction power VDMOS device obtained from the first tape-out experiment has a good super junction column morphology,with a breakdown voltage test result of 627 V and a specific on-resistance of 10.34mΩ·cm~2,meeting the requirements of the project.3.On the basis of meeting the requirements for the static characteristics of the device,the tolerance of the breakdown voltage is optimized,and a P-pillar non-uniform doping technology and a termination with resistive field plate are adopted to increase the design window of the breakdown voltage.This design has been validated by experimental results,creating conditions for dynamic characteristic optimization.To study and optimize the switching characteristics of the device,an additional P-type implantation in the active region is performed to reduce the gate-to-drain capacitance of the super junction power VDMOS device,and the switching speed of the device is improved.Then,the additional P-type implantation technology is applied to the gate region of the device to further improve the switching characteristics.The effectiveness of these two methods has been verified by experimental results.Finally,research and optimization are conducted on the reverse recovery characteristics of the device.The method of adjusting the doping concentration of the P-type lateral connection layer in the terminal region is used to improve the reverse recovery characteristics of the device and increase its softness factor.The feasibility of this optimization method is also verified through experimental results.