Edge termination structures for semiconductor devices
Semiconductor devices, and more particularly semiconductor devices with improved edge termination structures are disclosed. A semiconductor device includes a drift region that forms part of an active region. An edge termination region is arranged along a perimeter of the active region and also includes a portion of the drift region. The edge termination region includes one or more sub-regions of an opposite doping type than the drift region and one or more electrodes may be capacitively coupled to the drift region by way of the one or more sub-regions. During a forward blocking mode for the semiconductor device, the one or more electrodes may provide a path that draws ions away from passivation layers that are on the edge termination region and away from the active region. In this manner, the semiconductor device may exhibit reduced leakage, particularly at higher operating voltages and higher associated operating temperatures.
1. A semiconductor device comprising:
a drift region comprising a first doping type;
an active region comprising a portion of the drift region;
an edge termination region in the drift region and arranged along a perimeter of the active region, the edge termination region comprising a plurality of sub-regions of a second doping type that is opposite the first doping type;
a first electrode electrically connected to the edge termination region, the first electrode configured to be coupled to a first potential when the semiconductor device is electrically activated;
a first passivation layer on the edge termination region; and
a second passivation layer on the edge termination region,
wherein the first passivation layer extends continuously over at least two adjacent sub-regions of the second doping type, and
wherein the second passivation layer extends into the active region and is positioned in between a gate interconnect and a source interconnect.
2. The semiconductor device of claim 1 , wherein the first passivation layer comprises an opening that is registered with a first sub-region of the plurality of sub-regions.
3. The semiconductor device of claim 2 , wherein the first electrode is electrically connected to the first sub-region through the opening in the first passivation layer.
4. The semiconductor device of claim 3 , wherein the first sub-region is arranged closer to a peripheral edge of the drift region than any other sub-region of the plurality of sub-regions.
5. The semiconductor device of claim 1 , further comprising a second electrode electrically connected to the edge termination region, the second electrode configured to be coupled to a second potential that is different from the first potential when the semiconductor device is electrically activated.
6. The semiconductor device of claim 5 , wherein the second electrode is connected to the drift region outside a periphery of the plurality of sub-regions.
7. The semiconductor device of claim 5 , further comprising a surface depletion protection region in the edge termination region, the surface depletion protection region comprising the first doping type with a higher doping concentration than the drift region.
8. The semiconductor device of claim 7 , wherein the second electrode is connected to the surface depletion protection region.
9. The semiconductor device of claim 8 , wherein the surface depletion protection region is outside a periphery of the plurality of sub-regions.
10. The semiconductor device of claim 9 , wherein the second electrode contacts the surface depletion protection region through the opening in the second passivation layer.
11. The semiconductor device of claim 1 , wherein a third passivation layer overlaps the second passivation layer in a direction toward an outer edge of the semiconductor device.
12. The semiconductor device of claim 1 , wherein the third passivation layer directly contacts the gate interconnect and the source interconnect.
13. The semiconductor device of claim 9 , wherein the second passivation layer directly contacts the surface depletion region.
14. The semiconductor device of claim 5 , wherein the second electrode does not contact the first passivation layer or the second passivation layer.
15. The semiconductor device of claim 1 , wherein the first passivation layer is in between the drift region and the second passivation layer.
16. A semiconductor device comprising:
a drift region comprising a first doping type;
an active region comprising a portion of the drift region;
an edge termination region in the drift region and arranged along a perimeter of the active region, the edge termination region comprising a plurality of sub-regions of a second doping type that is opposite the first doping type;
a first passivation layer on the edge termination region;
a second passivation layer on the first passivation layer;
a surface depletion protection region in the edge termination region, the surface depletion protection region comprising the first doping type with a higher doping concentration than the drift region; and
an electrode electrically connected to the surface depletion protection region and extending through the first and second passivation layers,
wherein the electrode is a second electrode, the semiconductor device further comprising a first electrode that is electrically connected to the edge termination region, and
wherein the first electrode is configured to be coupled to a first potential when the semiconductor device is electrically activated and the second electrode is configured to be coupled to a second potential that is different from the first potential when the semiconductor device is electrically activated.
17. The semiconductor device of claim 16 , wherein the second potential is a drain potential of the semiconductor device.
18. The semiconductor device of claim 16 , wherein the surface depletion protection region is outside a periphery of the plurality of sub-regions.
19. The semiconductor device of claim 16 , wherein the first passivation layer comprises a first opening that is registered with a first sub-region of the plurality of sub-regions.
20. The semiconductor device of claim 19 , wherein the first electrode is electrically connected to the first sub-region through the first opening in the first passivation layer.
21. The semiconductor device of claim 20 , wherein the first passivation layer comprises a second opening and the second electrode contacts the surface depletion protection region through the second opening in the first passivation layer.
22. The semiconductor device of claim 16 , further comprising a third passivation layer on the first passivation layer and on the second passivation layer, wherein the first electrode is arranged between the third passivation layer and the drift region.
23. The semiconductor device of claim 16 , further comprising a scribe region adjacent to the edge termination region such that the edge termination region is between the scribe region and the active region, wherein an upper surface of the drift region is exposed in the scribe region.
24. A semiconductor device comprising:
a drift region comprising a first doping type;
an active region comprising a portion of the drift region;
an edge termination region in the drift region and arranged along a perimeter of the active region, the edge termination region comprising a plurality of sub-regions of a second doping type that is opposite the first doping type, wherein each sub-region comprises a guard ring;
a first passivation layer on the edge termination region and extending continuously over at least some of the plurality of sub-regions;
a second passivation layer on the first passivation layer and extending continuously over the at least some of the plurality of sub-regions;
a third passivation layer on the second passivation layer opposite the first passivation layer; and
a first electrode that contacts a first of the plurality of sub-regions;
wherein at least one guard ring is not connected to an electrode.
25. The semiconductor device of claim 24 , wherein a first portion of the edge termination region is outside a periphery of the plurality of sub-regions.
26. The semiconductor device of claim 25 , wherein the first portion of the edge termination region comprises a surface depletion protection region, the surface depletion protection region having a higher doping concentration of the first doping type than the drift region.
27. The semiconductor device of claim 26 , further comprising a second electrode that contacts the first portion of the edge termination region that has the first doping type.
28. The semiconductor device of claim 27 , wherein the first passivation layer further comprises a first opening that is registered with a first sub-region of the plurality of sub-regions and a second opening, where the first electrode contacts the first sub-region through the first opening and the second electrode contacts the surface depletion protection region through the second opening.
29. The semiconductor device of claim 24 , wherein the third passivation layer overlaps the second passivation layer in a direction toward an outer edge of the semiconductor device.
30. The semiconductor device of claim 27 , wherein the second electrode does not contact the first passivation layer or the second passivation layer.