| 摘要 |
A trench MOSFET is formed in a structure which includes a P-type epitaxial layer overlying an N+ substrate. A trench is formed in the epitaxial layer. A drain-drift region is formed by implanting N-type dopant through the bottom of the trench at different energies, creating a stack of N-type regions that extend from the bottom of the trench to the substrate. The energy and implant dose of the regions are set such that doping concentration of the drain-drift region increases monotonically with increasing depth below the bottom of the trench.
|
