Design And Manufacture Of Gate ESD Protected Trench MOSFET

Power MOSFETs are an important class of discrete devices for a variety of power conversion applications because of high input impedance, high switching frequency,large output current, good thermal stability and large safe operating area.It is being widely applied in the electronics equipments such as buttery protection , switching-mode power supply, DC-DC converter , synchronous rectifiers and etc.In this paper, a gate ESD protected Trench MOSFET is designed. The innovation is that this kind of Trench MOSFET get better ability on enduring ESD than normal MOSFET. The purpose of this article is to reduce the cost by decreasing the mask quantity and reducing RDSON per unit area.The first part of this article is the research background. It includes the development, application and market prospects of power MOSFET and the ESD protected MOSFET. The second part is the theory including the basic theory of Trench MOSFET and ESD. Making ESD structure at the Gate PAD field is also be presented, this method can reduce die size effectively. The third part is the engineering practice. firstly, the Epi spec is get by a academic expressions; the terminal introduce a special structure with Field-board, poly Guard-ring and Stop-ring together; manufacturing ESD diode on the method of P type doping first and then N type implant so that N type implant can be formed at the same time with N+ source implant, by this way we can reduce one mask layer; Tsuprem4 and Medici software are used to get the basic condition of the process, after analyzing the result of engineering lot CP data, FT data and HBM ESD data, then the best design is selected which achieves expected aim very well.