Power semiconductor device with embedded field electrodes
View Patent ↗A power semiconductor device is disclosed. The power semiconductor device includes an upper drift region situated over a lower drift region, a field electrode embedded in the lower drift region, the field electrode not being directly aligned with a gate trench in a body region of the power semiconductor device, where respective top surfaces of the field electrode and the lower drift region are substantially co-planar. A conductive filler in the field electrode can be substantially uniformly doped, and the field electrode is in direct electrical contact with the upper drift region.
1. A power semiconductor device comprising:
an upper drift region situated over a lower drift region;
a field electrode embedded in said lower drift region;
said field electrode not being directly aligned with a gate trench in a body region of said power semiconductor device;
wherein respective top surfaces of said field electrode and said lower drift region are substantially co-planar;
wherein said gate trench runs lengthwise in a direction parallel to said top surface of said lower drift region;
wherein said field electrode is situated in a trench in said lower drift region that runs lengthwise along the same direction as said gate trench.
2. The power semiconductor device of claim 1 , wherein said field electrode comprises a conductive filler and an insulation material in said trench in said lower drift region.
3. The power semiconductor device of claim 1 , wherein said field electrode comprises polysilicon.
4. The power semiconductor device of claim 1 , wherein said field electrode comprises amorphous silicon.
5. The power semiconductor device of claim 1 , wherein said field electrode is held at approximately an intermediate potential between a source and a drain of said power semiconductor device under reverse bias.
6. The power semiconductor device of claim 1 , further comprising another field electrode in said lower drift region, wherein said top surface of said field electrode is substantially co-planar with a top surface of said another field electrode.
7. The power semiconductor device of claim 1 , wherein said field electrode is situated below a source of said power semiconductor device.
8. The power semiconductor device of claim 1 , wherein said field electrode is in direct electrical contact with said upper drift region.
9. A power semiconductor device comprising:
an upper drift region situated over a lower drift region;
a field electrode embedded in said lower drift region;
said field electrode not being directly aligned with a gate trench in a body region of said power semiconductor device;
wherein respective top surfaces of said field electrode and said lower drift region are substantially co-planar;
wherein said gate trench runs lengthwise in a direction parallel to said top surface of said lower drift region;
wherein a conductive filler in said field electrode is substantially uniformly doped;
wherein said field electrode is situated in a trench in said lower drift region that runs lengthwise along the same direction as said gate trench.
10. The power semiconductor device of claim 9 , wherein said field electrode comprises a conductive filler and an insulation material in said trench in said lower drift region.
11. The power semiconductor device of claim 9 , wherein said field electrode comprises polysilicon.
12. The power semiconductor device of claim 9 , wherein said field electrode comprises amorphous silicon.
13. The power semiconductor device of claim 9 , wherein said field electrode is held at approximately an intermediate potential between a source and a drain of said power semiconductor device under reverse bias.
14. The power semiconductor device of claim 9 , further comprising another field electrode in said lower drift region, wherein said top surface of said field electrode is substantially co-planar with a top surface of said another field electrode.
15. The power semiconductor device of claim 9 , wherein said field electrode is situated below a source of said power semiconductor device.
16. The power semiconductor device of claim 9 , wherein said field electrode is in direct electrical contact with said upper drift region.