Power devices, structures, components, and methods using lateral drift, fixed net charge, and shield
View Patent ↗Lateral power devices where immobile electrostatic charge is emplaced in dielectric material adjoining the drift region. A shield gate is interposed between the gate electrode and the drain, to reduce the Miller charge. In some embodiments the gate electrode is a trench gate, and in such cases the shield electrode too is preferably vertically extended.
1. A semiconductor device comprising:
an n-type source region;
a p-type body region interposed between said source region and a p-type semiconductor further region;
a gate electrode which is capacitively coupled to controllably invert a portion of said body region, to controllably form therein a channel which connects said source region to said further region;
wherein said further region is laterally interposed between said body region and an n-type drain region;
permanent positive charge, which is embedded in at least one insulating region which adjoins said further region, and which inverts a layer of said further region in proximity to said insulating region;
a shield electrode not overlapping with said gate electrode, which is at least partly interposed between said gate electrode and said drain to reduce capacitive coupling between said gate and said drain; and
a dielectric-filled trench which is within said further region and vertically extends beyond said further region, and which lies at least partly beneath said gate electrode; and
wherein said gate electrode and said shield electrode both have a minimum width which is more than a respective maximum vertical thickness thereof.
2. The semiconductor device of claim 1 , wherein said further region is formed as a well.
3. The semiconductor device of claim 1 , further comprising a buried region within said further region.
4. The semiconductor device of claim 1 , wherein said channel and said further region both carry current flow in a predominantly horizontal plane.
5. The semiconductor device of claim 1 , wherein said channel lies in a plane which is predominantly normal to the plane of current flow in said further region.
6. The semiconductor device of claim 1 , wherein said channel lies in a plane which is predominantly normal to the surface of a semiconductor die, and said further region carries current flow which is predominantly parallel to said surface.
7. The semiconductor device of claim 1 , wherein said gate electrode and said shield electrode are both predominantly planar.
8. The semiconductor device of claim 1 , wherein said gate electrode and said shield electrode both lie in the same plane of metallization.
9. The semiconductor device of claim 1 , wherein said shield electrode is connected to a fixed potential, but said gate electrode is not.
10. The semiconductor device of claim 1 , wherein said further region is part of a semiconductor-on-insulator structure.