Termination structure for insulated gate semiconductor device and method
A semiconductor device structure includes a region of semiconductor material having an active region and a termination region. An active structure is disposed in the active region and a termination structure is disposed in the termination region. In one embodiment, the termination structure includes a termination trench and a conductive structure within the termination trench and electrically isolated from the region of semiconductor material by a dielectric structure. A dielectric layer is disposed to overlap the termination trench to provide the termination structure as a floating structure. A Schottky contact region is disposed within the active region. A conductive layer is electrically connected to the Schottky contact region and the first conductive layer extends onto a surface of the dielectric layer and laterally overlaps at least a portion of the termination trench.
1. A semiconductor device structure, comprising:
a region of semiconductor material comprising:
a first conductivity type;
a first major surface;
a second major surface opposite to the first major surface;
an active region; and
a termination region;
an active structure disposed in the active region comprising:
a first active trench extending from the first major surface into the region of semiconductor material to a first depth; and
a first conductive structure within the first active trench and electrically isolated from the region of semiconductor material by a first dielectric structure, wherein the first active trench has a first width proximate to the first major surface;
a termination structure disposed in the termination region comprising:
a first termination trench extending from the first major surface into the region of semiconductor material to a second depth;
a second conductive structure within the first termination trench and electrically isolated from the region of semiconductor material by a second dielectric structure, wherein:
the first termination trench comprises:
a second width proximate to the first major surface;
a first side surface;
a second side surface opposite to the first side surface; and
a first lower surface extending between the first side surface and the second side surface;
the first side surface is interposed between the second side surface and the first active trench; and
the second conductive structure comprises:
a first conductive spacer disposed proximate to the first side surface of the first termination trench; and
a second conductive spacer disposed proximate to the second side surface of the first termination trench; and
a dielectric layer disposed overlying at least a portion of the first lower surface of the first termination trench and overlying at least a portion of the second conductive spacer;
a doped structure comprising a second conductivity type opposite to the first conductivity type in the region of semiconductor material disposed adjacent to the first major surface and adjacent to the second side surface of the first termination trench;
a Schottky contact structure having a first portion disposed adjacent to the first major surface on opposing sides of the first active trench; and
a first conductive layer disposed overlying the first major surface and electrically coupled to the first portion of the Schottky contact structure and electrically coupled to the doped structure.
2. The semiconductor device of claim 1 , wherein:
the doped structure is further disposed adjacent to the first lower surface of the first termination trench.
3. The semiconductor device of claim 2 , wherein:
the doped structure comprises a plurality of doped regions that overlap.
4. The semiconductor device of claim 2 , wherein:
the doped structure is further disposed adjacent to the first side surface of the first termination trench.
5. The semiconductor device of claim 2 , wherein:
an opening is disposed within the dielectric layer proximate to the first lower surface of the first termination trench; and
the first conductive layer is further electrically coupled to the doped structure through the opening.
6. The semiconductor device of claim 5 , wherein:
a second portion of the Schottky contact structure is disposed within the doped structure adjacent to the first major surface; and
a third portion of the Schottky contact structure is disposed within doped structure proximate to the opening.
7. The semiconductor device of claim 2 , wherein:
the doped structure comprises a continuous doped structure.
8. The semiconductor device of claim 1 , further comprising:
a doped region comprising the second conductivity type in the region of semiconductor material adjacent to the first major surface, wherein:
the doped structure is interposed between the doped region and the second side surface of the first termination trench; and
the doped region is laterally spaced apart from the doped structure.
9. The semiconductor device of claim 8 , wherein:
the doped region comprises an electrically floating region.
10. The semiconductor device of claim 9 , wherein:
a dielectric region is disposed overlying a portion of the major surface adjacent to the doped region; and
the first conductive layer laterally overlaps at least a portion of the doped region in a cross-sectional view.
11. The semiconductor device of claim 1 , wherein:
the conductive layer is electrically coupled to the first conductive spacer.
12. The semiconductor device of claim 1 , wherein;
the region of semiconductor material comprises a substrate and a semiconductor layer disposed overlying the substrate;
the semiconductor layer provides the first major surface; and
the semiconductor device further comprises:
a substrate contact structure extending from the first major surface into the substrate.
13. A semiconductor device structure, comprising:
a region of semiconductor material comprising:
a first conductivity type;
a first major surface;
a second major surface opposite to the first major surface;
an active region; and
a termination region;
an active structure disposed in the active region;
a termination structure disposed in the termination region comprising:
a termination trench extending from the first major surface into the region of semiconductor material;
a first conductive structure within the termination trench and electrically isolated from the region of semiconductor material by a first dielectric structure, wherein:
the termination trench comprises:
a first side surface;
a second side surface opposite to the first side surface; and
a first lower surface extending between the first side surface and the second side surface;
the first side surface is interposed between the second side surface and the active trench; and
the first conductive structure comprises a first conductive spacer disposed proximate to the first side surface of the termination trench; and
a dielectric layer disposed overlying at least a portion of the first lower surface of the termination trench and overlapping at least a portion of the first conductive spacer;
a first doped region comprising a second conductivity type opposite to the first conductive type in the region of semiconductor material adjacent to the first lower surface of the termination trench;
a Schottky contact structure having a first portion disposed adjacent to the first major surface between the termination trench structure and the active structure; and
a first conductive layer disposed overlying the first major surface and electrically coupled to the first portion of Schottky contact structure and electrically coupled to the first doped region.
14. The semiconductor device of claim 13 , further comprising:
a second doped region comprising the second conductivity type in the region of semiconductor material adjacent to the lower surface of the termination trench and laterally spaced apart from the first doped region, wherein:
the second doped region is electrically decoupled from the first conductive layer.
15. The semiconductor device of claim 13 , wherein:
the dielectric layer comprises an opening adjacent to the first doped region proximate to the lower surface of the termination trench; and
the first conductive layer electrically coupled to the first doped region through the opening.
16. The semiconductor device of claim 15 , wherein:
the active structure comprises:
an active trench extending from the first major surface into the region of semiconductor material; and
a second conductive structure within the active trench and electrically isolated from the region of semiconductor material by a second dielectric structure; and
the first conductive layer is electrically connected to the first conductive spacer.
17. The semiconductor device of claim 13 , further comprising:
a second doped region comprising the second conductivity type in the region of semiconductor material adjacent to the first side surface of the termination trench and electrically coupled to the first doped region, wherein:
the first conductive layer is electrically coupled to the second doped region proximate to the first side surface of the first termination trench.
18. The semiconductor device of claim 13 , wherein:
the first termination has a width; and
the first doped region laterally extends the width.
19. The semiconductor device of claim 13 , wherein:
the region of semiconductor material comprises a substrate and a semiconductor layer disposed overlying the substrate;
the semiconductor layer provides the first major surface; and
the semiconductor device further comprises:
a substrate contact structure extending from the first major surface into the substrate.
20. A method of making a semiconductor device structure, comprising:
providing a region of semiconductor material comprising:
a first conductivity type;
a first major surface;
a second major surface opposite to the first major surface;
an active region; and
a termination region;
providing an active structure disposed in the active region comprising:
a first active trench extending from the first major surface into the region of semiconductor material; and
a first conductive structure within the first active trench and electrically isolated from the region of semiconductor material by a first dielectric structure;
providing a termination structure disposed in the termination region comprising:
a first termination trench extending from the first major surface into the region of semiconductor material;
a second conductive structure within the first termination trench and electrically isolated from the region of semiconductor material by a second dielectric structure, wherein:
the first termination trench comprises:
a first side surface;
a second side surface opposite to the first side surface; and
a first lower surface extending between the first side surface and the second side surface;
the first side surface is interposed between the second side surface and the first active trench; and
the second conductive structure comprises:
a first conductive spacer disposed proximate to the first side surface of the first termination trench; and
a second conductive spacer disposed proximate to the second side surface of the first termination trench;
providing a doped structure comprising a second conductivity type opposite to the first conductivity type in the region of semiconductor material disposed adjacent to the first major surface, adjacent to the second side surface of the first termination trench, and adjacent to the first lower surface of the first termination trench;
providing a dielectric layer disposed overlying the first lower surface of the first termination trench and overlying at least a portion of the second conductive spacer;
providing a Schottky contact structure disposed adjacent to the first major surface on opposing sides of the first active trench; and
providing a first conductive layer disposed overlying the first major surface and electrically coupled to the Schottky contact structure and electrically coupled to the doped structure.