Modeling And Optimization Of Body Diode Reverse Recovery Characteristics Of Ldmos Transistors

As switching speeds for DC-DC converter applications keep becoming faster and faster and voltage requirements become smaller and smaller, the need for new device structures becomes more prevalent. Designers of these new structures will need to make sure they take into consideration the different power losses associated with the different structures and make modifications to reduce or if possible eliminate them. A new 30V LDMOS device has been created and is being implemented into a synchronous buck converter for future DC-DC conversions. This new lateral device has a Figure of Merit of 80mÙ*nC, representing a 50% reduction from the conventional trench MOSFET. The only draw back with this new device is that the body diode power loss has increased significantly. There are two principal goals of this research. The first is to reduce the body diode reverse recovery characteristics of a 30V LDMOS transistor without employing an additional Schottky diode, increasing the Figure of Merit, or decreasing the breakdown voltage past 30 volts. The second is to achieve 75% reduction in reverse recovery charge (Qrr) through each solution. Four solutions will be presented in this study and have been verified through extensive ISE-TCAD device and circuit simulation