Design And Optimization Of 100V Shielded Gate Trench Power MOSFET

In the field of low-voltage and medium-voltage power devices,trench power MOSFETs are widely used in power management and consumer electronics due to their advantages of low on-resistance and fast switching speed.However,due to the restriction of the breakdown voltage,the on-resistance of the power MOSFET is difficult to greatly reduce.The shielded gate trench power MOSFET based on the two-dimensional charge coupling principle breaks the limit of the silicon limit theory,and can reduce the switching power loss while reducing the conduction power loss.With my country’s continuous emphasis on energy conservation and emission reduction,it has the great significance to research and design a high-performance shielded gate trench power MOSFET,and to optimize the structure on this basis.This thesis first introduces the main static and dynamic parameters of the shielded-gate trench power MOSFET,and provides the corresponding physical model to provide a certain basic theory for subsequent device design and optimization.Then designed a cell structure of a 100V shielded gate trench power MOSFET based on the 12-inch process platform,combined with the designed process,and used Sentaurus TCAD simulation software for structural modeling,then optimized some main parameters of the cell structure and analyze its impact on device performance,finally get a set of structural parameter combinations that satisfy the design requirements.And the simulation results show that the breakdown voltage of optimized cell structure is 113.6V,the characteristic on-resistance is34.4mΩ·mm²,and the characteristic gate-drain charge is 1.50n C/mm².Compared with products of the same specification on the market,this design has excellent device performance.Then the deep trench terminal structure and the overall layout layout that meet the pressure requirements are designed.Finally,in order to optimize the vertical electric field distribution in the drift region of the shielded gate trench power MOSFET,this paper partly replaces the insulating layer on the sidewall of the trench with a high-k insulating dielectric,and proposes a high-k shielded gate trench power MOSFET structure.By reasonably controlling the length and dielectric constant of the high-k medium to increase the electric field intensity in the centre of the drift region,the on-resistance can be reduced by increasing the doping concentration of the epitaxial layer while ensuring the same breakdown voltage.In addition,because the high-k dielectric improves the shielding effect of the coupling electrode on the gate electrode,the parasitic gate-drain capacitance and gate charge can be reduced,and the switching performance of the device is effectively improved.The simulation results show that compared with the optimized shielded gate trench power MOSFET,the characteristic on-resistance and the characteristic gate-drain charge of the shielded gate trench power MOSFET are reduced by 11.3%and 10.7%respectively on the basis of a small increase in breakdown voltage,and the device figure of merit(R_on,sp×Q_GD,SP)that comprehensively reflects these two parameters is reduced by 20.7%.