| In recent years,the IC industry has developed rapidly,and the ever-increasing domestic market demand for longer lasting batter-powered electronic devices and more efficient power supply have made the improvement of the efficiency of power management systems become more and more important..For a low-voltage power trench MOSFET,which is mainly used in DC-DC converters or microprocessors,its working efficiency often directly affects the working efficiency of the whole circuit.The presence of its parasitic diodes limits its efficiency.In order to avoid the reverse recovery characteristics of the parasitic body diode,a Schottky diode is used in parallel to achieve this.How to integrate Schottky diodes with power MOSFETs is especially important.Based on some existing integrated structures,in this thesis,the Schottky contacts is formed at the bottom of the trench contact holes of the original Trench VDMOS,and then the purpose of integrating Schottky diodes is achieved.Compared with the traditional integrated structure which divided the whole chip into two parts,one is the Trench MOSFET and the other is the Schottky diode.The structure used in this paper can form a Schottky contact between each Trench and don't need separately Schottky diode region on the chip,which greatly saves the chip area.Firstly,the influence of its structural parameters on the breakdown voltage,threshold voltage,forward conduction characteristics and reverse recovery characteristics of the device is analyzed by simulation,and the optimal structural parameters are obtained.Based on this,the terminal structure of the device is designed,and ultimately,the published drawings and determine the process flow for the entire device are determined.Through simulation,the device designed to have a breakdown voltage of 40V,a threshold voltage of 1.6V,an on-resistance of Rdson=12.6m?·mm2(Vgs=10V).the reverse recovery charge is5.35nC,and the reverse recovery time is 25.46ns?IF=1A,di/dt=100A/?s?.The preset indicator has been reached. |
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