Design And Implementation Of A Vehicle-Grade SGT MOSFET

After years of development,the Shielded-Gate Trench MOSFET has become a new type of power device that has been put into commercial use.The introduction of a shielded gate optimizes the electric field distribution,making the SGT MOSFET have excellent characteristics such as low on-resistance,high breakdown voltage,low switching losses,and simple drive.Therefore,SGT MOSFET can be widely used in new energy vehicle power management and intelligent vehicle systems.However,with the increasing sales of new energy vehicles,few domestic SGT MOSFET devices can meet the automotivegrade standards.In this context,the aim of this project is to design a 100 V SGT MOSFET that meets automotive-grade reliability standards to meet the needs of new energy vehicle applications.Firstly,this article analyzed the structure and performance parameters of ShieldedGate Trench MOSFET(SGT MOSFET)and used Sentaurus simulation tools to obtain the required range of structural parameters for the target design parameters,and determined the process parameters for device flow.Subsequently,based on the simulation results,the device was fabricated and tested through process window verification and package testing.The test results showed that the designed SGT MOSFET had a breakdown voltage of 107.3V and an on-resistance of1.91mΩ,which met the design target.Finally,this article optimized and improved the reliability of the designed device.Solutions were proposed to address three reliability issues,including polyimide bottom cracks,nitride layer cracks,and wire bonding failures that appeared in the first reliability assessment.The designed 100 V SGT MOSFET adopted a passivation layer structure of1μm nitride with a 75° slope on the surface and an 8μm I-type polyimide layer,which passed the AEC-Q101 reliability assessment and achieved the automotive-grade application standard.