Edge termination structure for a power integrated device and corresponding manufacturing process

Patent metadata

Field	Value
Publication number	US-9515136-B2
Application number	US-201514666013-A
Country	US
Kind code	B2
Filing date	Mar 23, 2015
Priority date	Jun 18, 2014
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

An integrated device has: a structural layer of semiconductor material doped with a first conductivity type and having a top surface defining a plane; a functional region, doped with a second conductivity type, arranged in an active area of the structural layer at the top surface, in the proximity of an edge area of the integrated device, which externally surrounds the active area; and an edge termination region, doped with the second conductivity type, joined to the functional region and arranged in the edge area. The edge termination region has a doping profile and a junction depth that vary in a first direction parallel to the plane.

First claim

The invention claimed is:

1. An integrated device, comprising:
a structural layer, including semiconductor material doped with a first conductivity type and having a top surface defining a plane;
a functional region doped with a second conductivity type and arranged in an active area of said structural layer at said top surface, near an edge area that externally surrounds said active area; and
an edge termination region doped with said second conductivity type, joined to said functional region, and arranged in said edge area, wherein said edge termination region has a doping profile and a junction depth that vary along a first direction parallel to said plane, wherein:
said edge termination region further has a doping profile that varies in a second direction orthogonal to said plane; and
said edge terminal region comprises first and second edge termination portions, the first edge terminal portion contacting said functional region and having a first junction depth in said structure layer and a first width in the first direction, the second edge terminal portion contacting and extending under the first edge terminal portion and having a second width in the first direction that is different from the first width.

2. The integrated device according to claim 1 , wherein said edge area is arranged between said active area and an external side wall of said structural layer and wherein said first direction is transverse to said external side wall.

3. The integrated device according to claim 1 , wherein each of said first and second edge termination portions has a variable profile of dopant concentration in said second direction, starting from a top surface of said edge termination portion down to the respective junction depth.

4. The integrated device according to claim 1 , wherein said first and second edge termination portions have respective charge amounts that are different from each other; wherein the charge amount of said first edge termination portion is greater than the charge amounts of the remaining edge termination portions and the charge amount of the second edge termination portion.

5. The integrated device according to claim 1 , wherein said structural layer includes silicon carbide.

6. The integrated device according to claim 1 , wherein said integrated device is a power device.

7. A process for manufacturing an integrated device, comprising:
providing a structural layer, including semiconductor material doped with a first conductivity type and having a top surface defining a plane;
forming a functional region, doped with a second conductivity type, in an active area of said structural layer at said top surface, near an edge area that externally surrounds said active area; and
forming an edge termination region, doped with said second conductivity type, joined to said functional region, and arranged in said edge area, wherein forming the edge termination region comprises providing said edge termination region with a doping profile and a junction depth that vary in a first direction parallel to said plane, wherein forming the edge termination region comprises:
providing the doping profile of said edge termination region that varies in a second direction orthogonal to said plane; and
forming a plurality of edge termination portions having respective widths in the first direction that are different from each other and respective junction depths in the second direction that are different from each other, wherein a top one of the edge termination portions contacts said functional region, and remaining edge termination portions of the plurality extend directly under the top edge termination portion.

8. The process according to claim 7 , wherein forming the plurality of edge termination portions comprises performing respective localized dopant implantations having respective implantation energies and respective dopant concentrations.

9. The method process according to claim 7 , wherein the width of said top edge termination portion is greater than the widths of the remaining edge termination portions, and the widths of the remaining edge termination portions decrease as a distance from said top edge termination portion increases.

10. The process according to claim 7 , wherein forming the plurality of edge termination portions comprises forming a first edge termination portion, which has a greater junction depth than the remaining edge termination portions, and subsequently forming the remaining edge termination portions starting from a second edge termination portion vertically overlapping the first edge termination portion up to said top edge termination portion.

11. The process according to claim 7 , wherein forming the plurality of edge termination portions comprises forming first said top edge termination portion and subsequently forming the remaining edge termination portions, starting from a first edge termination portion arranged vertically underneath the top edge termination portion down to a deep second edge termination portion having the greatest junction depth.

12. The process according to claim 7 , wherein forming the plurality of edge termination portions comprises performing a corresponding plurality of dopant implantations through respective implantation masks; each of said implantations being followed by a respective step of thermal activation of the implanted dopants.

13. An integrated device, comprising:
a structural layer, including semiconductor material doped with a first conductivity type and having a top surface defining a plane;
a functional region doped with a second conductivity type and arranged in an active area of said structural layer at said top surface, near an edge area that externally surrounds said active area; and
an edge termination region doped with said second conductivity type, joined to said functional region, and arranged in said edge area, wherein said edge termination region has a doping profile and a junction depth that vary along a first direction parallel to said plane, wherein said edge termination region comprises a plurality of edge termination portions, arranged adjacent to one another in mutual contact, a first of said edge termination portions being connected to said functional region; said edge termination portions having respective junction depths in said structural layer that are distinct from each other, wherein said edge termination portions have respective widths in said first direction that are different from each other and said edge termination portions are positioned directly under each other.

14. The integrated device according to claim 13 , wherein each of said edge termination portions has a variable profile of dopant concentration in a second direction, which is orthogonal from the plane.

15. An integrated device, comprising:
a structural layer, including semiconductor material doped with a first conductivity type and having a top surface defining a plane;
a functional region doped with a second conductivity type and arranged in an active area of said structural layer at said top surface, near an edge area that externally surrounds said active area; and
an edge termination region doped with said second conductivity type, joined to said functional region, and arranged in said edge area, wherein said edge termination region has a doping profile and a junction depth that vary along a first direction parallel to said plane, wherein the edge termination region comprises forming a plurality of doped regions having said second conductivity type, the doped regions having respective junction depths in said structural layer; at least one of said doped regions

Assignees

• St Microelectronics Srl

Inventors

• Fragapane Leonardo

Classifications

• H10P30/2044

  into semiconducting carbon, e.g. diamond or semiconducting diamond-like carbon · CPC title

• H10P30/22

  using masks · CPC title

• H10W10/031

  of isolation regions comprising PN junctions · CPC title

• H10W10/30

  Isolation regions comprising PN junctions · CPC title

• H10D64/111

  Field plates · CPC title